net: Make dn_ptr depend on CONFIG_DECNET

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index df5241c..4bd4ad7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8134,8 +8134,9 @@ void netdev_run_todo(void)
 		BUG_ON(!list_empty(&dev->ptype_specific));
 		WARN_ON(rcu_access_pointer(dev->ip_ptr));
 		WARN_ON(rcu_access_pointer(dev->ip6_ptr));
+#if IS_ENABLED(CONFIG_DECNET)
 		WARN_ON(dev->dn_ptr);
-
+#endif
 		if (dev->priv_destructor)
 			dev->priv_destructor(dev);
 		if (dev->needs_free_netdev)