net: hinic: fix bug that ethtool get wrong stats

Function hinic_get_stats64() will do two operations:
1. reads stats from every hinic_rxq/txq and accumulates them
2. calls hinic_rxq/txq_clean_stats() to clean every rxq/txq's stats

For hinic_get_stats64(), it could get right data, because it sums all
data to nic_dev->rx_stats/tx_stats.
But it is wrong for get_drv_queue_stats(), this function will read
hinic_rxq's stats, which have been cleared to zero by hinic_get_stats64().

I have observed hinic's cleanup operation by using such command:
> watch -n 1 "cat ethtool -S eth4 | tail -40"

Result before:
     ...
     rxq7_pkts: 1
     rxq7_bytes: 90
     rxq7_errors: 0
     rxq7_csum_errors: 0
     rxq7_other_errors: 0
     ...
     rxq9_pkts: 11
     rxq9_bytes: 726
     rxq9_errors: 0
     rxq9_csum_errors: 0
     rxq9_other_errors: 0
     ...
     rxq11_pkts: 0
     rxq11_bytes: 0
     rxq11_errors: 0
     rxq11_csum_errors: 0
     rxq11_other_errors: 0

Result after a few seconds:
     ...
     rxq7_pkts: 0
     rxq7_bytes: 0
     rxq7_errors: 0
     rxq7_csum_errors: 0
     rxq7_other_errors: 0
     ...
     rxq9_pkts: 2
     rxq9_bytes: 132
     rxq9_errors: 0
     rxq9_csum_errors: 0
     rxq9_other_errors: 0
     ...
     rxq11_pkts: 1
     rxq11_bytes: 170
     rxq11_errors: 0
     rxq11_csum_errors: 0
     rxq11_other_errors: 0

To solve this problem, we just keep every queue's total stats in their own
queue (aka hinic_{rxq|txq}), and simply sum all per-queue stats every time
calling hinic_get_stats64().
With that solution, there is no need to clean per-queue stats now,
and there is no need to maintain global hinic_dev.{tx|rx}_stats, too.

Fixes: edd384f6 ("net-next/hinic: Add ethtool and stats")
Signed-off-by: Qiao Ma <mqaio@linux.alibaba.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>