vfio/igd: Check vendor and device ID on GVT-g mdev

vfio/igd: Check vendor and device ID on GVT-g mdev

Check the vendor and device ID on GVT-g mdev to ensure it is a supported
device [1]. This extra check is required for automatically enabling
OpRegion access later.

Note that Cherryview and Gemini Lake are marked as supported here since
current code cannot distinguish them with other Gen8 and Gen9 devices.
Since mdev cannot be created on these devices, this has no functional
impact.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/i915/intel_gvt.c?h=v6.14#n52

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250505170305.23622-5-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>