leds: led-class: Fix checkpatch warning

Fixes the following checkpatch warning:
WARNING: Prefer netdev_dbg(netdev, ... then dev_dbg(dev, ... then pr_debug(...  to printk(KERN_DEBUG ...
FILE: leds/led-class.c:214:
	printk(KERN_DEBUG "Registered led device: %s\n",
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/led-class.c

@@ -211,7 +211,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 	led_trigger_set_default(led_cdev);
 #endif
 
-	printk(KERN_DEBUG "Registered led device: %s\n",
+	dev_dbg(parent, "Registered led device: %s\n",
 			led_cdev->name);
 
 	return 0;