media: ccs: Move media_entity_pads_init to init from register

The media entity will soon need to be initialised before the sub-device
init finalisation that allocates memory for sub-device state. Do that now.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>