"off_t" and the return value is a "paddr_t" to allow mappings
at offsets past 2^31 bytes. Somewhat inspired by FreeBSD, which
only changed the offset to a "vm_offset_t".
Includes updates for the i386, pc532 and sh3 mmmmap from Jason Thorpe.
- there are a couple of registers that are reset after the X server finishes,
which do not have the same values as they do when the machine is powered
on. If the two are mismatched you can't write to the video memory.
- video memory is mapped at offset 4MB to keep the X server happy
- there is now a VGA memory mapping
- DEBUG_ET4000 is now a bit more useful for debugging!
simonb