Figure out how to get the qemu-litex emulation working with fupy.

[mithro]

We have the start of qemu emulation for litex at https://github.com/timvideos/qemu-litex -- it would be really awesome if this could be used to allow people to develop micropython for FPGAs without needing the real hardware.

Obviously this only works for things like liteEth which have a more stable API and QEmu emulation. This won't work when people are doing custom gateware.