When memory mapping a PCI device (like XFree86 does) on an XP1000, we must
use ALPHA_PHYS_TO_K0SEG(offset) rather than just plain offet. I've verified
that this does not break other platforms (I've tested an AlphaStation 200
and a Personal Workstation 500au with this patch).

As to why this works, well.. Its black magic as far as I know. I obtained
this hack from Myricom, who in turn, obtained it from Compaq engineers.
Without this hack, XFree86 cannot talk to a PCI graphics card.

Reviewed by: Doug Rabson <dfr@nlsystems.com>
Obtained from: feldy@myri.com (Bob Felderman)