net: hns3: format the output of the MAC address

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: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>