net: hns3: add querying speed and duplex support to VF

This patch adds support for querying speed and duplex by ethtool ethX
to VF.

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>