PM / devfreq: remove redundant null pointer check before kfree

kfree has taken the null pointer into account. hence it is safe
to remove the redundant null pointer check before kfree.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/devfreq.c

@@ -713,8 +713,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq_remove_device(devfreq);
 	devfreq = NULL;
 err_dev:
-	if (devfreq)
-		kfree(devfreq);
+	kfree(devfreq);
 err_out:
 	return ERR_PTR(err);
 }