This only required a minor patch to the usb-designware driver due
to DMA requiring physical addresses -- on the X1000, these differ
from virtual addresses so we have to do the usual conversion.
Both the mass storage and HID drivers work, but there are a few
issues so this can't be considered 100% stable yet.
- Mass storage might not be detected properly on insertion,
and USB has to be replugged before it shows up
- HID driver may occasionally panic or hang the machine
Change-Id: Ia3ce7591d5928ec7cbca7953abfef01bdbd873ef