leds: led-class: set permissions on max_brightness file to 0444

max_brightness is not writable, thus set permissions to 0444.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/leds/led-class.c

@@ -74,7 +74,7 @@ static ssize_t led_max_brightness_show(struct device *dev,
 
 static struct device_attribute led_class_attrs[] = {
 	__ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
-	__ATTR(max_brightness, 0644, led_max_brightness_show, NULL),
+	__ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
 #ifdef CONFIG_LEDS_TRIGGERS
 	__ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
 #endif