power: reset: gpio-poweroff: add missing MODULE_DEVICE_TABLE

This patch adds missing MODULE_DEVICE_TABLE definition which generates
correct modalias for automatic loading of this driver when it is built
as an external module.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Bixuan Cui <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/reset/gpio-poweroff.c

···
 	{ .compatible = "gpio-poweroff", },
 	{},
 };
+MODULE_DEVICE_TABLE(of, of_gpio_poweroff_match);
 
 static struct platform_driver gpio_poweroff_driver = {
 	.probe = gpio_poweroff_probe,