MFC r254852:

drm: Update drm_pciids.h based on Linux 3.8

This header can be easily updated using the new "gen-drm_pciids" script,
available in tools/tools/drm. The script uses the Linux' drm_pciids.h
header for new IDs, the FreeBSD's one because we add the name of the
device to each IDs, and the PCI IDs database (misc/pciids port) to fill
this name automatically for new IDS.

To call the script:
  tools/tools/drm/gen-drm_pciids					\
    /path/to/linux/drm_pciids.h						\
    /path/to/freebsd/drm_pciids.h					\
    /path/to/pciids/pci.ids