platform/x86: thinkpad_acpi: Add LED_RETAIN_AT_SHUTDOWN to led_class_devs

Add the LED_RETAIN_AT_SHUTDOWN flag to the registered led_class_devs so
that the LEDs do not get turned-off when reloading the driver and thus so
that they also stay under default EC control when reloading the driver,
unless explicitly overridden by the user.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211123210524.266705-1-hdegoede@redhat.com

drivers/platform/x86/thinkpad_acpi.c

@@ -5809,6 +5809,7 @@ static int __init tpacpi_init_led(unsigned int led)
 		tpacpi_leds[led].led_classdev.brightness_get = &led_sysfs_get;
 
 	tpacpi_leds[led].led_classdev.name = tpacpi_led_names[led];
+	tpacpi_leds[led].led_classdev.flags = LED_RETAIN_AT_SHUTDOWN;
 	tpacpi_leds[led].led = led;
 
 	return led_classdev_register(&tpacpi_pdev->dev, &tpacpi_leds[led].led_classdev);