[media] sh-mobile-ceu-camera: add primitive OF support

Add an OF hook to sh_mobile_ceu_camera.c, no properties so far. Booting
with DT also requires platform data to be optional.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>