net: hisilicon: Fix hns_mdio module autoload for OF registration

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/net/ethernet/hisilicon//hns_mdio.ko | grep alias
alias:          platform:Hi-HNS_MDIO
alias:          acpi*:HISI0141:*

After this patch:

$ modinfo drivers/net/ethernet/hisilicon//hns_mdio.ko | grep alias
alias:          platform:Hi-HNS_MDIO
alias:          of:N*T*Chisilicon,hns-mdioC*
alias:          of:N*T*Chisilicon,hns-mdio
alias:          of:N*T*Chisilicon,mdioC*
alias:          of:N*T*Chisilicon,mdio
alias:          acpi*:HISI0141:*
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns_mdio.c

@@ -563,6 +563,7 @@ static const struct of_device_id hns_mdio_match[] = {
 	{.compatible = "hisilicon,hns-mdio"},
 	{}
 };
+MODULE_DEVICE_TABLE(of, hns_mdio_match);
 
 static const struct acpi_device_id hns_mdio_acpi_match[] = {
 	{ "HISI0141", 0 },