vfio/igd: remove unsupported device ids

vfio/igd: remove unsupported device ids

Since e433f208973f ("vfio/igd: return an invalid generation for unknown
devices"), the default return of igd_gen() was changed to unsupported.
There is no need to filter out those unsupported devices.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Link: https://lore.kernel.org/r/20241206122749.9893-3-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>