media: v4l2-dev: disable frequency and tuner ioctls for touch

Touch devices have obviously no tuner, so don't attempt to enable those
ioctls for such devices.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>