Bus widths should now all be correct. (addresses and sizes in amaranth
take into account the granularity selection, so granularity acts like
two extra bits on the bus address line)
Also don't ignore a warning about undriven resets. Turns out that can
gate *everything* off in your design.
This was causing my nextpnr crash. I really do need to figure out how to
do this in a less hacky way. Or even just make it more explicit that I
am doing this for a reason.