V4L/DVB (11118): cafe_ccic: replace debugfs with g/s_register ioctls.

Using VIDIOC_DBG_S/G_REGISTER is the standard way of reading/writing register
for advanced debugging under v4l2. In addition, using this means that the
cafe_ccic driver doesn't need to have knowledge about the used sensor: the
debug ioctl can be passed on to the sensor if it isn't for the host.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>