memory area's base and limit are optional. The low 4-bits of the "low"
prefetchable registers indicates whether or not a 32-bit or 64-bit
region is supported. The PCI-PCI driver had been assuming that all bridges
supported a 64-bit region (and thus the two upper 32-bit registers). Fix
the driver to only use those registers if the low 4-bits of the "low"
registers indicate that a 64-bit region is supported. The PCI-PCI bridge
in the XBox happens to be a bridge that only supports a 32-bit region.
Reported by: rink
MFC after: 1 week
d2bd463b11