V4L/DVB (7244): ivtv: CROP is not supported for video capture

CROPCAP suggests that video capture supports cropping, but this is not the
case.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>