leds: core: Refactor led_update_brightness() to use standard pattern

The standard conditional pattern is to check for errors first and
bail out if any. Refactor led_update_brightness() accordingly.

While at it, drop unneeded assignment and return 0 unconditionally
on success.

Signed-off-by: Andy Shevchenko <[e-mail]>
Acked-by: Denis Osterland-Heim <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/leds/led-core.c

···
 
 int led_update_brightness(struct led_classdev *led_cdev)
 {
-	int ret = 0;
+	int ret;
 
 	if (led_cdev->brightness_get) {
 		ret = led_cdev->brightness_get(led_cdev);
-		if (ret >= 0) {
-			led_cdev->brightness = ret;
-			return 0;
-		}
+		if (ret < 0)
+			return ret;
+
+		led_cdev->brightness = ret;
 	}
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(led_update_brightness);