net: phy: mdio-gpio: Fix module autoload for OF platform driver

This platform driver has a OF device ID table but the OF module
alias information is not created so module autoloading won't work.
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mdio-gpio.c

@@ -261,6 +261,7 @@ static const struct of_device_id mdio_gpio_of_match[] = {
 	{ .compatible = "virtual,mdio-gpio", },
 	{ /* sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
 
 static struct platform_driver mdio_gpio_driver = {
 	.probe = mdio_gpio_probe,