net: hns3: fix a bug for phy supported feature initialization

This patch fixes a bug for phy supported feature initialization.
Currently, the value of phydev->supported is initialized by kernel.
So it includes many features that we do not support, such as
SUPPORTED_FIBRE and SUPPORTED_BNC. This patch fixes it.

Fixes: 256727da (net: hns3: Add MDIO support to HNS3 Ethernet driver for hip08 SoC)
Signed-off-by: Fuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: Lipeng <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>