net: hns3: Fixes the ether address copy with appropriate API

This patch replaces the ethernet address copy instance with more
appropriate ether_addr_copy() function.

Fixes: 6427264ef330 ("net: hns3: Add HNS3 Acceleration Engine &
Compatibility Layer Support")
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>