loop: don't freeze the queue in lo_release

loop: don't freeze the queue in lo_release

By the time the final ->release is called there can't be outstanding I/O.
For non-final ->release there is no need for driver action at all.

Thus remove the useless queue freeze.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220330052917.2566582-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>