net: hns: fix to intimate the link-status change by adding LF/RF method

In current scenario, when the interface is disabled we reset the XGMAC
RX/TX functionality. This operation does not affects the PHY layer/SFP
and which appears UP to the remote end(this behaviour is unlike GMAC).
The result is remote end keeps on sending the packets which gets partly
processed by XMAC and dropped. Since these are partly processed these
appears as errored packets in the packet counter statistics.

This patch fixes this behaviour and adds local-fault and remote-fault
functionality which can be used to intimate the remote peer whenever
the state of the interface changes. This patch also removes the
existing hns_dsaf_xge_core_srst_by_port function which was being used
to reset the RX/TX functionality at XGE Core.

Reported-by: Jun He <hjat2005@huawei.com>
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>