Dummy out all of the PCI bus and device access control functions. We
need a better way to do this, and that will probably be in
libpciaccess and / or the kernel.
Refactor xf86GetPciInfoForEntity to use pci_device_find_by_slot.
Refector xf86CheckPciSlot to use xf86GetPciEntity.
Eliminate disablePciBios and the one place that calls it.