net: add Hisilicon Network Subsystem basic ethernet support

This is to add basic ethernet support for HNS. It is one of the way to
use the HNS acceleration engine. But most of the decoding/encoding
capability of the AE cannot be used in this way.

This submit contains the basic feature as a ethernet driver. More will
be added later.

Signed-off-by: huangdaode <huangdaode@hisilicon.com>
Signed-off-by: Kenneth Lee <liguozhu@huawei.com>
Signed-off-by: Yisen Zhuang <Yisen.Zhuang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>