[media] v4l2-core/v4l2-ctrls: Filter NOOP CH_RANGE events

If modify_range is called but no range is changed, do not send the
CH_RANGE event.

Reported-by: Dimitrios Katsaros <patcherwork@gmail.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>