net: dsa: sja1105: Reverse TPID and TPID2

>From reading the P/Q/R/S user manual, it appears that TPID is used by
the switch for detecting S-tags and TPID2 for C-tags.  Their meaning is
not clear from the E/T manual.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -1421,8 +1421,8 @@ static int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled)
 
 	if (enabled) {
 		/* Enable VLAN filtering. */
-		tpid  = ETH_P_8021Q;
-		tpid2 = ETH_P_8021AD;
+		tpid  = ETH_P_8021AD;
+		tpid2 = ETH_P_8021Q;
 	} else {
 		/* Disable VLAN filtering. */
 		tpid  = ETH_P_SJA1105;
@@ -1431,7 +1431,9 @@ static int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled)
 
 	table = &priv->static_config.tables[BLK_IDX_GENERAL_PARAMS];
 	general_params = table->entries;
+	/* EtherType used to identify outer tagged (S-tag) VLAN traffic */
 	general_params->tpid = tpid;
+	/* EtherType used to identify inner tagged (C-tag) VLAN traffic */
 	general_params->tpid2 = tpid2;
 
 	rc = sja1105_static_config_reload(priv);