net: dsa: sja1105: remove set but not used variables 'tx_vid' and 'rx_vid'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/dsa/sja1105/sja1105_main.c: In function sja1105_fdb_dump:
drivers/net/dsa/sja1105/sja1105_main.c:1226:14: warning:
 variable tx_vid set but not used [-Wunused-but-set-variable]
drivers/net/dsa/sja1105/sja1105_main.c:1226:6: warning:
 variable rx_vid set but not used [-Wunused-but-set-variable]

They are not used since commit 6d7c7d948a ("net: dsa:
sja1105: Fix broken learning with vlan_filtering disabled")

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -1223,12 +1223,8 @@ static int sja1105_fdb_dump(struct dsa_switch *ds, int port,
 {
 	struct sja1105_private *priv = ds->priv;
 	struct device *dev = ds->dev;
-	u16 rx_vid, tx_vid;
 	int i;
 
-	rx_vid = dsa_8021q_rx_vid(ds, port);
-	tx_vid = dsa_8021q_tx_vid(ds, port);
-
 	for (i = 0; i < SJA1105_MAX_L2_LOOKUP_COUNT; i++) {
 		struct sja1105_l2_lookup_entry l2_lookup = {0};
 		u8 macaddr[ETH_ALEN];