mlxsw: spectrum: Disable learning according to STP state

When port is put into LISTENING state it shouldn't populate the FDB, so
set the port's STP state in hardware to DISCARDING instead of LEARNING.
It will therefore keep listening to BPDU packets, but discard other
non-control packets and won't perform any learning.

Fixes: 56ade8fe ("mlxsw: spectrum: Add initial support for Spectrum ASIC")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c

@@ -127,10 +127,10 @@ static int mlxsw_sp_port_stp_state_set(struct mlxsw_sp_port *mlxsw_sp_port,
 	case BR_STATE_FORWARDING:
 		spms_state = MLXSW_REG_SPMS_STATE_FORWARDING;
 		break;
-	case BR_STATE_LISTENING: /* fall-through */
 	case BR_STATE_LEARNING:
 		spms_state = MLXSW_REG_SPMS_STATE_LEARNING;
 		break;
+	case BR_STATE_LISTENING: /* fall-through */
 	case BR_STATE_DISABLED: /* fall-through */
 	case BR_STATE_BLOCKING:
 		spms_state = MLXSW_REG_SPMS_STATE_DISCARDING;