net-next/hinic:fix a bug in set mac address

In add_mac_addr(), if the MAC address is a muliticast address,
it will not be set, which causes the network card fail to receive
the multicast packet. This patch fixes this bug.

Signed-off-by: Xue Chaojing <xuechaojing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>