[media] v4l: omap4iss: Remove video node crop support

Cropping should be configured on the pipeline subdev nodes, not through
the video nodes. Remove crop support on all video nodes.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>