net: hns: Add self-adaptive interrupt coalesce support in hns driver

When deal with low and high throughput, it is hard to achiece both
high performance and low latency. In order to achiece that, this patch
calculates the rx rate, and adjust the interrupt coalesce parameter
accordingly.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Tested-by: Weiwei Deng <dengweiwei@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>