IB/mlx4: Remove deprecated create_singlethread_workqueue

alloc_ordered_workqueue() with WQ_MEM_RECLAIM set, replaces
deprecated create_singlethread_workqueue(). This is the identity
conversion.

The workqueue "wq" queues work items &dm[i]->work, &ew->work.
It has been identity converted.

WQ_MEM_RECLAIM has been set to ensure forward progress under
memory pressure.
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx4/main.c

@@ -3244,7 +3244,7 @@ static int __init mlx4_ib_init(void)
 {
 	int err;
 
-	wq = create_singlethread_workqueue("mlx4_ib");
+	wq = alloc_ordered_workqueue("mlx4_ib", WQ_MEM_RECLAIM);
 	if (!wq)
 		return -ENOMEM;