net: hns3: fix for getting auto-negotiation state in hclge_get_autoneg

When phy exists, we use the value of phydev.autoneg to represent the
auto-negotiation state of hardware. Otherwise, we use the value of
mac.autoneg to represent it.

This patch fixes for getting a error value of auto-negotiation state in
hclge_get_autoneg().

Fixes: 46a3df9f

 ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support")
Signed-off-by: Fuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>