ublk: remove the check of ublk_need_req_ref() from __ublk_check_and_get_req

__ublk_check_and_get_req() is only called from ublk_check_and_get_req()
and ublk_register_io_buf(), the same check has been covered in the two
calling sites.

So remove the check from __ublk_check_and_get_req().

Suggested-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250429022941.1718671-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Ming Lei

drivers/block/ublk_drv.c

@@ -2148,9 +2148,6 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub,
 {
 	struct request *req;
 
-	if (!ublk_need_req_ref(ubq))
-		return NULL;
-
 	req = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], tag);
 	if (!req)
 		return NULL;