Revert "block/mq-deadline: use correct way to throttling write requests"

The code "max(1U, 3 * (1U << shift)  / 4)" comes from the Kyber I/O
scheduler. The Kyber I/O scheduler maintains one internal queue per hwq
and hence derives its async_depth from the number of hwq tags. Using
this approach for the mq-deadline scheduler is wrong since the
mq-deadline scheduler maintains one internal queue for all hwqs
combined. Hence this revert.

Cc: stable@vger.kernel.org
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Cc: Zhiguo Niu <Zhiguo.Niu@unisoc.com>
Fixes: d47f9717

 ("block/mq-deadline: use correct way to throttling write requests")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240313214218.1736147-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>