mlxsw: acl: Introduce ACL trap and forward action

Use trap/discard flex action to implement trap and forward. The action will
later be used for multicast routing, as the multicast routing mechanism is
done using ACL flexible actions in Spectrum hardware. Using that action, it
will be possible to implement a trap-and-forward route.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>