net: hns: bug fix of ethtool show the speed

When run ethtool ethX on hns driver, the speed will show
as "Unknown". The base.speed is not correct assigned,
this patch fix this bug.

Signed-off-by: Daode Huang <huangdaode@hisilicon.com>
Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>