net: hns3: prevent unnecessary MAC TNL interrupt

MAC TNL interrupt is used to collect statistic info about
link status changing suddenly when netdev is running.

But when stopping netdev, the enabled MAC TNL interrupt is
unnecessary, and may add some noises to the statistic info.
So this patch disables it before stopping MAC.

Fixes: a6345787

 ("net: hns3: Add handling of MAC tunnel interruption")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Reviewed-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>