led: make led_set_brightness_sync() use led_set_brightness_nosleep()

Making led_set_brightness_sync() use led_set_brightness_nosleep() has 2
advantages:
- works for LED controllers that do not provide brightness_set_blocking()
- When the blocking callback is used, it uses the workqueue to update the
  LED state, removing the need for mutual exclusion between
  led_set_brightness_sync() and set_brightness_delayed().

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/leds/led-core.c

@@ -294,15 +294,17 @@ EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 int led_set_brightness_sync(struct led_classdev *led_cdev,
 			    enum led_brightness value)
 {
+	int ret;
+
 	if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 		return -EBUSY;
 
-	led_cdev->brightness = min(value, led_cdev->max_brightness);
-
-	if (led_cdev->flags & LED_SUSPENDED)
-		return 0;
+	ret = led_set_brightness_nosleep(led_cdev, value);
+	if (!ret)
+		return ret;
 
-	return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
+	flush_work(&led_cdev->set_brightness_work);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(led_set_brightness_sync);