fs: streamline thaw_super_locked

Add a new out_unlock label to share code that just releases s_umount
and returns an error, and rename and reuse the out label that deactivates
the sb for one more case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231027064001.GA9469@lst.de


Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>