media: v4l2-fwnode: Remove v4l2_async_notifier_parse_fwnode_endpoints_by_port()

There are no users left of this helper and as it implements an
undesirable and too simple behaviour that should instead be implemented
directly by drivers remove it to prevent future uses of it.

Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>