[media] v4l: Mark VIDIOC_SUBDEV_G_CROP and VIDIOC_SUBDEV_S_CROP obsolete

These two IOCTLS are obsoleted by VIDIOC_SUBDEV_G_SELECTION and
VIDIOC_SUBDEV_S_SELECTION. Mark them obsolete.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>