net: hns3: fix wrong size of mailbox responding data

According to user manual, the maximum size of mailbox responding
data is 8 bytes, the macro HCLGE_MBX_MAX_RESP_DATA_SIZE
should be defined as 8 instead of 16.

Fixes: 9194d18b ("net: hns3: fix the problem that the supported port is empty")
Signed-off-by: Zhongzhu Liu <liuzhongzhu@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>