net: hns3: refactor PF/VF RSS hash key configuration

In order to make it more readable, this patch modifies PF/VF's
RSS hash key configuring function.

Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Weihang Li <liweihang@hisilicon.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>