LWIP is broken due to CAmkES DMA changes that honor caching flags now

[axel-h]

https://github.com/seL4/util_libs/blob/master/libethdrivers/src/lwip.c uses dma_alloc_pin() with cached=1. With the recent changes in seL4/camkes-tool@ac567a1 that make CAmkES honor the caching flag, this is broken now - there is no cached DMA pool available, just an uncached on.

Quick fix is using cached=0 everywhere, as DMA in ARM/RISC-V us usually uncached. Things might be different on x86, I'm not really an expert there... Aside from this, it seems the LWIP version here lost active maintenance some tiume back and it's unclear how well this is working anyway.