net: dsa: rtl8366: Fix up VLAN filtering

We get this regression when using RTL8366RB as part of a bridge
with OpenWrt:

WARNING: CPU: 0 PID: 1347 at net/switchdev/switchdev.c:291
	 switchdev_port_attr_set_now+0x80/0xa4
lan0: Commit of attribute (id=7) failed.
(...)
realtek-smi switch lan0: failed to initialize vlan filtering on this port

This is because it is trying to disable VLAN filtering
on VLAN0, as we have forgot to add 1 to the port number
to get the right VLAN in rtl8366_vlan_filtering(): when
we initialize the VLAN we associate VLAN1 with port 0,
VLAN2 with port 1 etc, so we need to add 1 to the port
offset.

Fixes: d8652956 ("net: dsa: realtek-smi: Add Realtek SMI driver")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/rtl8366.c

@@ -307,7 +307,8 @@ int rtl8366_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering)
 	struct rtl8366_vlan_4k vlan4k;
 	int ret;
 
-	if (!smi->ops->is_vlan_valid(smi, port))
+	/* Use VLAN nr port + 1 since VLAN0 is not valid */
+	if (!smi->ops->is_vlan_valid(smi, port + 1))
 		return -EINVAL;
 
 	dev_info(smi->dev, "%s filtering on port %d\n",
@@ -318,12 +319,12 @@ int rtl8366_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering)
 	 * The hardware support filter ID (FID) 0..7, I have no clue how to
 	 * support this in the driver when the callback only says on/off.
 	 */
-	ret = smi->ops->get_vlan_4k(smi, port, &vlan4k);
+	ret = smi->ops->get_vlan_4k(smi, port + 1, &vlan4k);
 	if (ret)
 		return ret;
 
 	/* Just set the filter to FID 1 for now then */
-	ret = rtl8366_set_vlan(smi, port,
+	ret = rtl8366_set_vlan(smi, port + 1,
 			       vlan4k.member,
 			       vlan4k.untag,
 			       1);