net/mlx5: Break encap/decap into two separated flow table creation flags

Today we are able to attach encap and decap actions only to the FDB. In
preparation to enable those actions on the NIC flow tables, break the
single flag into two. Those flags control whatever a decap or encap
operations can be attached to the flow table created. For FDB, if
encapsulation is required, we set both of them.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>