leds: ledtrig-backlight: Properly pass on max_brightness property

We had that hardcoded to LED_FULL (which did not matter until
now).
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

drivers/leds/trigger/ledtrig-backlight.c

@@ -146,7 +146,7 @@ static int bl_trig_activate(struct led_classdev *led)
 
 	memset(&props, 0, sizeof(struct backlight_properties));
 	props.type = BACKLIGHT_PLATFORM;
-	props.max_brightness = LED_FULL;
+	props.max_brightness = led->max_brightness;
 	props.brightness = led->brightness;
 	n->backlight_device = backlight_device_register(led->name,
 							led->dev,