net/mlx5e: Support offloading double vlan push/pop tc actions

As we can configure two push/pop actions in one flow table entry,
add support to offload those double vlan actions in a rule to HW.

Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>