LinuxKPI: add pci_ids.h

brcm80211 include pci_ids.h directly while historically we were tracking
IDs in pci.h. Move the current set of IDs from pci.h to pci_ids.h and
while here add IDs for Realtek and Broadcom as well as a network class
as needed by their wireless drivers.

We still include pci_ids.h from pci.h so this should not change anything.

MFC-after: 2 weeks
Reviewed-by: hselasky
Differential Revision: https://reviews.freebsd.org/D29400