media: v4l2-subdev: Remove non-pad dv timing callbacks

After the conversion of dv timing calls to use a pad argument is done,
remove the old callbacks. Update the subdev ioctl handlers to use the
new callbacks.

Signed-off-by: Paweł Anikiel <panikiel@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>