media: ccs: Correct error handling in ccs_register_subdev

ccs_register_subdev() did not clean up the media entity in error case, do
that now. Also switch to goto based error handling.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>