net: hns3: fix for phy_addr error in hclge_mac_mdio_config

When phy exists, phy_addr must less than PHY_MAX_ADDR.
If not, hclge_mac_mdio_config should return error.
And for fiber(phy_addr=0xff), it does not need hclge_mac_mdio_config.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>