net: gianfar_ptp: 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>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/gianfar_ptp.c

@@ -557,6 +557,7 @@ static const struct of_device_id match_table[] = {
 	{ .compatible = "fsl,etsec-ptp" },
 	{},
 };
+MODULE_DEVICE_TABLE(of, match_table);
 
 static struct platform_driver gianfar_ptp_driver = {
 	.driver = {