net: hns3: don't allow user to change vlan filter state

When user disables vlan filter, and adds vlan device, it won't
notify the driver the update the vlan filter. In this case, when
user enables vlan filter again, the packets with new vlan tag
will be filtered by vlan filter.

Signed-off-by: Jian Shen <shenjian15@huawei.com>
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>