net/hns3: fix MAC and queues HW statistics overflow

net/hns3: fix MAC and queues HW statistics overflow

The MAC and queues statistics are 32-bit registers in hardware. If
hardware statistics are not obtained for a long time, these statistics
will be overflow.
So PF and VF driver have to periodically obtain and save these
statistics. Since the periodical task and the stats API are in different
threads, we introduce a statistics lock to protect the statistics.

Fixes: 8839c5e202f3 ("net/hns3: support device stats")
Cc: stable@dpdk.org
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Signed-off-by: Min Hu (Connor) <humin29@huawei.com>