intel: Cleanup SKL PCI ID definitions.

This removes ones which aren't used, and adds some new ones. I kept the original
names where possible.

Cc: Kristian Høgsberg <krh@bitplanet.net>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>