Fix targets which fail to build

[mithro]

As of commit 1ef75a5 the following builds fail;

The following builds failed!
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arty bridge_net lm32
arty bridge_net or1k
arty ddr3 lm32
arty ddr3 or1k
mimasv2 base lm32
mimasv2 base or1k
mimasv2 memtest lm32
mimasv2 memtest or1k
mimasv2 scope lm32
mimasv2 scope or1k
netv2 bridge_pcie lm32
netv2 bridge_pcie or1k
netv2 bridge_uart lm32
netv2 bridge_uart or1k
netv2 pcie lm32
netv2 pcie or1k
netv2 video lm32
netv2 video or1k
nexys_video bridge_net lm32
nexys_video bridge_net or1k
nexys_video ddr3 lm32
nexys_video ddr3 or1k
nexys_video etherbone lm32
nexys_video etherbone or1k
opsis hdmi2usb or1k
opsis memtest lm32
opsis memtest or1k
opsis video_out_debug lm32
opsis video_out_debug or1k