agp/intel: Add pci id for hostbridge from has/qemu

This is needed to run the simulator.

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: added a comment in case people wonder what it's for.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>