net: hns3: format the output of the MAC address

driver inclusion
category: cleanup
bugzilla: NA
CVE: NA

----------------------------

Printing the whole MAC addresse may bring security risks. Therefore,
the MAC address is partially encrypted to improve security.

Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Reviewed-by: Yongxin Li <liyongxin1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>