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/ata/sata_nv.c b/drivers/ata/sata_nv.c
index cdf99fa..1db6f5c 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -1951,7 +1951,7 @@
 	ata_id_c_string(dev->id, model_num, ATA_ID_PROD, sizeof(model_num));
 
 	if (strncmp(model_num, "Maxtor", 6) == 0) {
-		ata_scsi_change_queue_depth(sdev, 1, SCSI_QDEPTH_DEFAULT);
+		ata_scsi_change_queue_depth(sdev, 1);
 		ata_dev_notice(dev, "Disabling SWNCQ mode (depth %x)\n",
 			       sdev->queue_depth);
 	}