media: Documentation: v4l: Fix async sensor subdev helper documentation

Document that the notifier of an async sub-device is, besider
unregistered, also cleaned up using v4l2_async_unregister_subdev().
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Documentation/driver-api/media/v4l2-subdev.rst

@@ -219,11 +219,11 @@ registering their async sub-devices with the notifier.
 Asynchronous sub-device registration helper for camera sensor drivers
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-:c:func:`v4l2_async_register_subdev_sensor` is a helper function for
-sensor drivers registering their own async sub-device, but it also registers a
-notifier and further registers async sub-devices for lens and flash devices
-found in firmware. The notifier for the sub-device is unregistered with the
-async sub-device.
+:c:func:`v4l2_async_register_subdev_sensor` is a helper function for sensor
+drivers registering their own async sub-device, but it also registers a notifier
+and further registers async sub-devices for lens and flash devices found in
+firmware. The notifier for the sub-device is unregistered and cleaned up with
+the async sub-device, using :c:func:`v4l2_async_unregister_subdev`.
 
 Asynchronous sub-device notifier example
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^