net/hns3: fix timing in mailbox

net/hns3: fix timing in mailbox

Currently, when processing MBX messages, the system timestamp is obtained
to determine whether timeout occurs. However, the gettimeofday function
is not monotonically increasing. Therefore, this may lead to incorrect
judgment or difficulty exiting the loop. And actually, in this scenario,
it is not necessary to obtain the timestamp.

This patch deletes the call to the gettimeofday function during MBX
message processing.

Fixes: 463e748964f5 ("net/hns3: support mailbox")
Cc: stable@dpdk.org
Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Min Hu (Connor) <humin29@huawei.com>