ftgmac100: Support NCSI VLAN filtering when available

Register the ndo_vlan_rx_{add,kill}_vid callbacks and set the
NETIF_F_HW_VLAN_CTAG_FILTER if NCSI is available.
This allows the VLAN core to notify the NCSI driver when changes occur
so that the remote NCSI channel can be properly configured to filter on
the set VLAN tags.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>