media: v4l2-mc: Mark v4l2_pipeline_link_notify() as deprecated

Commit b97213a41140 ("media: v4l2-mc: Make v4l2_pipeline_pm_{get,put}
deprecated") marked the v4l2_pipeline_pm_get() and
v4l2_pipeline_pm_put() functions as deprecated, but forgot to address
the related v4l2_pipeline_link_notify() function similarly. Fix it.

Signed-off-by: Laurent Pinchart <[e-mail]>
Acked-by: Sakari Ailus <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Laurent Pinchart <[e-mail]>

include/media/v4l2-mc.h

···
  * @flags: New link flags that will be applied
  * @notification: The link's state change notification type (MEDIA_DEV_NOTIFY_*)
  *
+ * THIS FUNCTION IS DEPRECATED. DO NOT USE IN NEW DRIVERS. USE RUNTIME PM
+ * ON SUB-DEVICE DRIVERS INSTEAD.
+ *
  * React to link management on powered pipelines by updating the use count of
  * all entities in the source and sink sides of the link. Entities are powered
  * on or off accordingly. The use of this function should be paired