[media] v4l: Remove V4L2 OF framework in favour of V4L2 fwnode framework

All drivers have been converted from V4L2 OF to V4L2 fwnode. The V4L2 OF
framework is now unused. Remove it.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>