mlxsw: spectrum: Fix gact_ok offloading

For ok GACT action, TERMINATE binding_cmd should be used in action set
passed down to HW.

Fixes: b2925957

 ("mlxsw: spectrum_flower: Offload "ok" termination action")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reported-by: Alexander Petrovskiy <alexpe@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>