net/mlx4_core: Preparation for VF vlan protocol 802.1ad

Check device capability to support VF vlan protocol 802.1ad mode.
Add vport attribute vlan protocol.
Init vport vlan protocol by default to 802.1Q.
Add update QP support for VF vlan protocol 802.1ad.
Add func capability vlan_offload_disable to disable all
vlan HW acceleration on VF while the VF is set to VF vlan protocol
802.1ad mode.
No change in VF vlan protocol 802.1Q (VST) mode.

Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>