LinuxKPI: add more #defines to pci.h

Add more definitions for various PCI uses to linux/pci.h. Almost all
are defined to their FreeBSD counterparts which are described there.

Sponsored by: The FreeBSD Foundation
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30434

(cherry picked from commit fc1d840901b1aefe22924d772781e2c835edb096)