net: hns: add media-type property for hns

It is PORT_TP type if the service port is GE mode. It is wrong to
judge the port type by using if it is service port. Adding the media
type to know port type.

Reported-by: Jinchuan Tian <tianjinchuan1@huawei.com>
Signed-off-by: Kejian Yan <yankejian@huawei.com>
Signed-off-by: Yisen Zhuang <Yisen.Zhuang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>