net: make vlan ndo_vlan_rx_[add/kill]_vid return error value

Let caller know the result of adding/removing vlan id to/from vlan
filter.

In some drivers I make those functions to just return 0. But in those
where there is able to see if hw setup went correctly, return value is
set appropriately.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>