Updating submodules.

 * litedram changed from edd5e0e to f51052f
    * f51052f - core/controller: fix burst_length regression introduced by timvideos#206. <Florent Kermarrec>
    * c4ac887 - Merge pull request timvideos#206 from antmicro/jboc/gensdrphy <enjoy-digital>
    * 2c5fc66 - phy/gensdrphy: fix problems with half-rate phy, tested on minispartan6 <Jędrzej Boczar>
    * 7f55e2e - phy/gensdrphy: add half-rate PHY <Jędrzej Boczar>

 * liteeth changed from dbe15f1 to 792013a
    * 792013a - mac/sram: avoid asynchronous read port on LiteEthMACSRAMReader (fix the resource usage issue identified in timvideos#43). <Florent Kermarrec>
    * 1d76d02 - frontend: rename tty to stream (tty was too specific since modules can be used for any kind of data stream). <Florent Kermarrec>

 * litepcie changed from 5668679 to 0b6a4bb
    * 0b6a4bb - software/kernel/main: enable up to 8 dma channels. <Florent Kermarrec>
    * f106f74 - software/user/litepcie_util: reset dma_test errors to 0 on each loop. <Florent Kermarrec>
    * 4d506fb - litepcie_gen: remove CSR software reset (no longer handled by software. <Florent Kermarrec>
    * f258b88 - phy/ultrascale: fix padding on s_axis_cc_header0 (requesterid was shifted by 1-bit). <Florent Kermarrec>
    * ccdd7a2 - core/msi/LitePCIeMSIX: avoid reserved registers when width > 32. <Florent Kermarrec>

 * litex changed from e7646416 to 9fc488bd
    *   9fc488bd - Merge pull request timvideos#597 from antmicro/jboc/litex-buildenv-add-adapter-fix <enjoy-digital>
    |\
    | * 07bc589c - fix/Vivado: don't instantiate wishbone.Converter in add_adapter when not needed <Jędrzej Boczar>
    * |   b9251950 - Merge pull request timvideos#595 from betrusted-io/master <enjoy-digital>
    |\ \
    | * | 53a567da - wire up missing register bits. <bunnie>
    * | |   87d7f6e7 - Merge pull request timvideos#598 from sergachev/master <enjoy-digital>
    |\ \ \
    | |_|/
    |/| |
    | * | 8656ea9b - interconnect/csr_bus: fix paged access warning <Ilia Sergachev>
    |/ /
    * | 4a18b828 - software/liblitesdcard/spisdcard: remove optimization on receive_block (not working on all configs) and increase max clk_freq to 20MHz. <Florent Kermarrec>
    * | 100aa5a4 - soc/cores/spi/SPIMaster: rewrite/simplify. - Make sure MOSI is latched on start, MISO is stable during Xfer (last value). - Allow clk_divider down to 2. - improve test errors reporting with hex() on AssertEqual. <Florent Kermarrec>
    |/
    * 63c19ff4 - liblitesdcard/spisdcard: update comments. <Florent Kermarrec>
    * 1f34f6ef - soc/cores/spi: make sure done and miso are synchronous. <Florent Kermarrec>
    * 754f140a - spisdcard: revert to 8-bit SPI, optimize spisdcardreceive_block and reduce clk to 12.5MHz for now. <Florent Kermarrec>
    * 8143f1a0 - soc/cores/spi: make sure miso is stable during xfer. <Florent Kermarrec>
    * ac35e158 - bios/boot: add bootargs support on netboot/sdcardboot to optionally specify r1/r2/r3/addr. <Florent Kermarrec>
    *   ee4b1d81 - Merge pull request timvideos#594 from antmicro/jboc/axi-lite <enjoy-digital>
    |\
    | * 229da572 - soc/interconnect/axi: propagate response errors in AXILiteDownConverter <Jędrzej Boczar>
    | * 93bcc94b - soc/interconnect/axi: implement AXILite down-converter <Jędrzej Boczar>
    * | 21c48eed - Merge pull request timvideos#593 from antmicro/jboc/axi-lite <enjoy-digital>
    |\|
    | * 0be607da - soc/integration: revert `bus` argument for add_ram/add_rom <Jędrzej Boczar>
    | * 2700ec3c - soc/integration: use AXILiteConverter (dummy implementation) in add_adapter() <Jędrzej Boczar>
    | * f3072d49 - soc/interconnect/axi: add connect methods for convenience <Jędrzej Boczar>
    | * 78a631f3 - test/axi: add AXILite2CSR and AXILiteSRAM tests <Jędrzej Boczar>
    | * a5be2cd2 - soc/interconnect/axi: improve SRAM/CSR access speed <Jędrzej Boczar>
    | * d8a242d8 - soc/interconnect: add AXILite SRAM <Jędrzej Boczar>
    | * b692b2a3 - soc/interconnect: add AXILite2CSR bridge <Jędrzej Boczar>
    | * 35149c4e - soc/integration: update add_adapter to convert between AXILite/Wishbone <Jędrzej Boczar>
    * |   e12bebb8 - Merge pull request timvideos#592 from antmicro/fix-symbiflow-makefile <enjoy-digital>
    |\ \
    | |/
    |/|
    | * 3f7568de - symbiflow: changed toolchain command names in Makefile <Alessandro Comodi>
    |/
    * 6671eb62 - build/lattice/trellis: set default spimode to None (--spimode not passed to ecppack) as default instead of fast-read. <Florent Kermarrec>
    * ae3c78f6 - build/lattice/trellis: fix spimode typo. <Florent Kermarrec>
    * 7c381dad - Merge pull request timvideos#588 from oskirby/trellis-spimode <enjoy-digital>
    * 0aec5b0f - trellis: Add option to select SPI mode. <Owen Kirby>

 * litex-boards changed from 1f98bc5 to 2ce24df
    * 2ce24df - platforms/genesys2: add internal_vref to 0.750v on bank 34 (DDR3). <Florent Kermarrec>
    * 135c387 - platforms/ulx3s: add assertion for supported devices. <Florent Kermarrec>
    * 851378f - platforms/trellisboard: move ddram_vtt_en. <Florent Kermarrec>
    *   165f9ea - Merge pull request timvideos#91 from antmicro/jboc/gensdrphy <enjoy-digital>
    |\
    | * 02f53e6 - targets/minispartan6: add support for HalfRateGENSDRPHY <Jędrzej Boczar>
    * 82f4553 - Merge pull request timvideos#90 from jersey99/master <enjoy-digital>
    * 44ad902 - platforms/kc705.py: LPC DP0_M2C/C2M diff pair <Vamsi K Vytla>

 * migen changed from 0.6.dev-351-gfa7bed2 to 0.6.dev-354-g7bc4eb1
    * 7bc4eb1 - xilinx: add DDRInput for Spartan6 (timvideos#214) <Thomas Spurden>
    * 731c192 - metlino: add SFP CTL pins <Harry Ho>
    * 12e7ba6 - Fix Si5324 reset. <Paweł Kulik>

Full submodule status
--
 2942d0652a89646c5225bee15dd55cc3b0871766 VexRiscv (1.0.1-417-g2942d06)
 3a6108a75be356a3dc53760d22782f1323248b6b edid-decode (heads/master)
 3a06aa84b62ad24467fb0d2c6ceddf565e9ea447 flash_proxies (heads/master)
 f51052f8b737156d1e257eff7cd3259cb56d0d1b litedram (2020.04-69-gf51052f)
 792013a1756ea50608726ee86989ec38cfc35a8b liteeth (2020.04-21-g792013a)
 6fdd02058fba29008c90b162e0ef707dce15ebeb liteiclink (2020.04)
 0b6a4bb6e742fd4de38d7ca3674f91acc5985b35 litepcie (2020.04-56-g0b6a4bb)
 b36d3a33fbbfcffdb77a7a9e05bc8121387858d3 litesata (2020.04-1-gb36d3a3)
 15179cb46f68bff1679631a8bade6f7e1607a40a litescope (2020.04-2-g15179cb)
 7457a29b1a47fe15e81fa37f3bbdd510788f1d53 liteusb (heads/master)
 41f30143075ece3fff5c33a332ed067d1837cbb3 litevideo (2020.04)
 9fc488bdf670c69193a6fa14e5f0c218db8b0ffe litex (2020.04-492-g9fc488bd)
 2ce24df76dda20cff9ac40c334300d5dc1311d60 litex-boards (2020.04-132-g2ce24df)
 f1792587a9b50732578e0166cb5d1d83b126cfa6 litex-renode (remotes/origin/HEAD)
 7bc4eb1387b39159a74c1dbd1b820728e0bfbbaa migen (0.6.dev-354-g7bc4eb1)
 8f5a253b22cd4ebcd56304a3662f4c70e3b34ed5 nmigen (v0.1-69-g8f5a253)
 48333804e40c7c9c1c8d5b2e70ba75f4b646d8f0 pythondata-cpu-lm32 (2020.04-5-g4833380)
 4731142284cf87e89b21fb35ceff1139f2f89227 pythondata-cpu-minerva (heads/master)
 af561171f5fc8c684537897f12ef0f429e38624b pythondata-cpu-mor1kx (2020.04-5-gaf56117)
 88974894c800ee2e827db47865e0611a07ff40d7 pythondata-cpu-picorv32 (2020.04-5-g8897489)
 654057b2f5cec0f9fc99487dff67861f76fcbe7e pythondata-cpu-vexriscv (2020.04-7-g654057b)
 7cfcaed2e726027fd622650b58dd77e47c495ee0 pythondata-software-compiler_rt (2020.04-5-g7cfcaed2)