o improves understandability by replacing numerous relative address
calculations with fixed addresses; everything should now match up
more easily with the vm layout shown at the top of the file
o move the expansion bus chip select regions to be contiguous with
the expansion bus configuration area; this is not exploited right
now but allows map consolidation in the future
o leave a gap between the expansion bus regions and the pci config
space in case we want to map more exp bus cs regions
Reviewed by: imp, thompsa
d4b227a5fa