scsi: sr: constify sr_pm_ops structure

sr_pm_ops, of type struct dev_pm_ops, is never modified, so declare it
as const.

Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sr.c

@@ -83,7 +83,7 @@ static int sr_init_command(struct scsi_cmnd *SCpnt);
 static int sr_done(struct scsi_cmnd *);
 static int sr_runtime_suspend(struct device *dev);
 
-static struct dev_pm_ops sr_pm_ops = {
+static const struct dev_pm_ops sr_pm_ops = {
 	.runtime_suspend	= sr_runtime_suspend,
 };