net: dsa: fix switch tree list

If there are multiple switch trees on the device, only the last one
will be listed, because the arguments of list_add_tail are swapped.

Fixes: 83c0afae ("net: dsa: Add new binding implementation")
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dsa/dsa2.c

@@ -46,7 +46,7 @@ static struct dsa_switch_tree *dsa_tree_alloc(int index)
 	dst->index = index;
 
 	INIT_LIST_HEAD(&dst->list);
-	list_add_tail(&dsa_tree_list, &dst->list);
+	list_add_tail(&dst->list, &dsa_tree_list);
 
 	kref_init(&dst->refcount);