Add support for st6422 bridge and sensor to the stv06xx gspca sub driver,
tested with:
Logitech QuickCam Messenger     046d:08f0       ST6422  integrated
Logitech QuickCam Mess. Plus    046d:08f6       ST6422  integrated
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>