net: hns3: refactor out hclge_set_vf_vlan_common()

To improve code readability and maintainability, separate
the command handling part and the status parsing part from
bloated hclge_set_vf_vlan_common().

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>