net/mlx5: Add support to s-tag in mlx5 firmware interface

Add svlan_tag and rename vlan_tag to cvlan_tag in flow table entry
match param.

Signed-off-by: Mohamad Haj Yahia <mohamad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>