platform/x86: asus-wmi: Do not disable keyboard backlight on unloading

The keyboard backlight is automatically disabled when the module is
unloaded as it is exposed as a ledclass device. Change this behavior to
ignore setting brightness when the device is in unloading state.
Signed-off-by: Yurii Pavlovskyi <yurii.pavlovskyi@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/asus-wmi.c

@@ -471,6 +471,10 @@ static void do_kbd_led_set(struct led_classdev *led_cdev, int value)
 static void kbd_led_set(struct led_classdev *led_cdev,
 			enum led_brightness value)
 {
+	/* Prevent disabling keyboard backlight on module unregister */
+	if (led_cdev->flags & LED_UNREGISTERING)
+		return;
+
 	do_kbd_led_set(led_cdev, value);
 }