[media] adv7180: Add media controller support

Add media controller support to the adv7180 driver by registering a media
entity instance for it as well as implementing pad ops for configuring the
format.

As there currently don't seem to be any users of the video ops format
operations those are removed as well in this patch.

Also set the V4L2_SUBDEV_FL_HAS_DEVNODE flag for the subdevice so it is
possible to create a subdevice device node.

Since the driver now depends on VIDEO_V4L2_SUBDEV_API all drivers which
select the driver need to depend on that symbol as well.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Federico Vaga <federico.vaga@gmail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>