PM / devfreq: create_freezable_workqueue() doesn't return an ERR_PTR

The create_freezable_workqueue() function returns a NULL on error and
not an ERR_PTR.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/devfreq.c

@@ -993,10 +993,10 @@ static int __init devfreq_init(void)
 	}
 
 	devfreq_wq = create_freezable_workqueue("devfreq_wq");
-	if (IS_ERR(devfreq_wq)) {
+	if (!devfreq_wq) {
 		class_destroy(devfreq_class);
 		pr_err("%s: couldn't create workqueue\n", __FILE__);
-		return PTR_ERR(devfreq_wq);
+		return -ENOMEM;
 	}
 	devfreq_class->dev_groups = devfreq_groups;