PCI: change PCI nomenclature in drivers/pci/ (non-comment changes)

PCI: change PCI nomenclature in drivers/pci/ (non-comment changes)

Changing occurrences of variants of PCI-X and PCIe to the PCI-SIG
terms listed in the "Trademark and Logo Usage Guidelines".
http://www.pcisig.com/developers/procedures/logos/Trademark_and_Logo_Usage_Guidelines_updated_112206.pdf

Patch is limited to drivers/pci/ and changes concern non-comment parts or
anything that might be visible to the user.

Signed-off-by: Stefan Assmann <sassmann@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>