VFS: move the start_dirop() kerndoc comment to before start_dirop()

VFS: move the start_dirop() kerndoc comment to before start_dirop()

This kerneldoc comment was always meant for start_dirop(), not for
__start_dirop() which is a static function and doesn't need
documentation.

It was in the wrong place and was then incorrectly renamed (instead of
moved) and useless "documentation" was added for "@state" was provided.

This patch reverts the name, removes the mention of @state, and moves
the comment to where it belongs.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20260224222542.3458677-4-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>