scsi: drop reason argument from ->change_queue_depth

Drop the now unused reason argument from the ->change_queue_depth method.
Also add a return value to scsi_adjust_queue_depth, and rename it to
scsi_change_queue_depth now that it can be used as the default
->change_queue_depth implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 0f7e4c7..22e7012 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -682,17 +682,13 @@
  * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
  * @sdev:	Virtscsi target whose queue depth to change
  * @qdepth:	New queue depth
- * @reason:	Reason for the queue depth change.
  */
-static int virtscsi_change_queue_depth(struct scsi_device *sdev,
-				       int qdepth,
-				       int reason)
+static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 {
 	struct Scsi_Host *shost = sdev->host;
 	int max_depth = shost->cmd_per_lun;
 
-	scsi_adjust_queue_depth(sdev, min(max_depth, qdepth));
-	return sdev->queue_depth;
+	return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
 }
 
 static int virtscsi_abort(struct scsi_cmnd *sc)