liquidio: implement vlan filter enable and disable

Add implementation to support ethtool -K ethX rx-vlan-filter on/off.
Rename OCTNET_CMD_ENABLE_VLAN_FILTER command to OCTNET_CMD_VLAN_FILTER_CTL
and add OCTNET_CMD_VLAN_FILTER_ENABLE and OCTNET_CMD_VLAN_FILTER_DISABLE
parameters so that it can be used to enable or disable the filter.

Signed-off-by: Prasad Kanneganti <prasad.kanneganti@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>