net: dsa: let switches specify their tagging protocol

In order to support the new DSA device driver model, a dsa_switch should
be able to advertise the type of tagging protocol supported by the
underlying switch device. This also removes constraints on how tagging
can be stacked to each other.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 6f02ccc5..4cc9956 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -227,7 +227,7 @@
 	 * switch.
 	 */
 	if (dst->cpu_switch == index) {
-		switch (drv->tag_protocol) {
+		switch (ds->tag_protocol) {
 #ifdef CONFIG_NET_DSA_TAG_DSA
 		case DSA_TAG_PROTO_DSA:
 			dst->rcv = dsa_netdev_ops.rcv;
@@ -255,7 +255,7 @@
 			goto out;
 		}
 
-		dst->tag_protocol = drv->tag_protocol;
+		dst->tag_protocol = ds->tag_protocol;
 	}
 
 	/*
@@ -364,6 +364,7 @@
 	ds->index = index;
 	ds->pd = pd;
 	ds->drv = drv;
+	ds->tag_protocol = drv->tag_protocol;
 	ds->master_dev = host_dev;
 
 	ret = dsa_switch_setup_one(ds, parent);