net/mlx4_en: Disable vlan HW acceleration when in VF vlan protocol 802.1ad mode

In Ethernet VF, disable vlan HW acceleration on VF
while it is set to VF vlan protocol 802.1ad 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>