net: hns3: refactor hns3_set_ringparam()

Use struct hns3_ring_param to replace variable new/old_xxx and
add hns3_is_ringparam_changed() to judge them if is changed to
improve code readability.

Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>