net: hns3: use memcpy to simplify code

Use memcpy to copy req->msg.resp_data to resp->additional_info,
to simplify the code and improve a little efficiency.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>