nvme-multipath: set QUEUE_FLAG_NOWAIT

The nvme multipathing code just dispatches bios to one of the blk-mq
based paths and never blocks on its own, so set QUEUE_FLAG_NOWAIT
to support REQ_NOWAIT bios.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>

drivers/nvme/host/multipath.c

@@ -465,6 +465,8 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 			ctrl->subsys->instance, head->instance);
 
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue);
+	blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue);
+
 	/* set to a default value of 512 until the disk is validated */
 	blk_queue_logical_block_size(head->disk->queue, 512);
 	blk_set_stacking_limits(&head->disk->queue->limits);