net: hns3: extract macro to simplify ring stats update code

As the code to update ring stats is alike for different ring stats
type, this patch extract macro to simplify ring stats update code.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>