net: hns: set xge statistic reg as read only

As the user manual of HNS V2 describs, XGE_DFX_CTRL_CFG.xge_dfx_ctrl_cfg
should be configed as zero if we want xge statistic reg to be read only.
But HNS V1 gets the other meanings. It needs to be identified the process
and then config it rightly.

Signed-off-by: Qianqian Xie <xieqianqian@huawei.com>
Signed-off-by: Yisen Zhuang <Yisen.Zhuang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>