block: Decode all flag names in the debugfs output

See also:
* Commit 4d337ceb ("blk-mq: avoid to touch q->elevator without any protection").
* Commit 414dd48e ("blk-mq: add tagset quiesce interface").

Cc: Christoph Hellwig <hch@lst.de>
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230518222708.1190867-1-bvanassche@acm.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>