PM / devfreq: fix duplicated kfree on devfreq pointer

device_unregister() calls kfree already.
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/devfreq.c

@@ -603,7 +603,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 err_init:
 	list_del(&devfreq->node);
 	device_unregister(&devfreq->dev);
-	kfree(devfreq);
 err_out:
 	return ERR_PTR(err);
 }