blk-mq: avoid re-initialize request which is failed in direct dispatch

blk-mq: avoid re-initialize request which is failed in direct dispatch

If we directly issue a request and it fails, we use
blk_mq_merge_queue_io(). But we already assigned bio to a request in
blk_mq_bio_to_request. blk_mq_merge_queue_io shouldn't run
blk_mq_bio_to_request again.

Orabug: 26339553
Suggested-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit 239ad215f0d8388cbe6c09a0fab8ad8ff5dba420)
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Bhavesh Davda <bhavesh.davda@oracle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>