dm rq: don't queue request to blk-mq during DM suspend

commit b4459b11 upstream.

DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.

But blk-mq's unquiesce may come from outside events, such as elevator
switch, updating nr_requests or others, and request may come during
suspend, so simply ask for blk-mq to requeue it.

Fixes one kernel panic issue when running updating nr_requests and
dm-mpath suspend/resume stress test.

Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
[Shivani: Modified to apply on 5.10.y]
Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>