net: dsa: assign a CPU port to DSA port

DSA ports also need to have a dedicated CPU port assigned to them,
because they need to know where to egress frames targeting the CPU,
e.g. To_Cpu frames received on a Marvell Tag port.
Signed-off-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dsa/dsa2.c

@@ -241,7 +241,7 @@ static int dsa_tree_setup_default_cpu(struct dsa_switch_tree *dst)
 		for (port = 0; port < ds->num_ports; port++) {
 			dp = &ds->ports[port];
 
-			if (dsa_port_is_user(dp))
+			if (dsa_port_is_user(dp) || dsa_port_is_dsa(dp))
 				dp->cpu_dp = dst->cpu_dp;
 		}
 	}