pkt_sched: Get rid of u32_list.

The u32_list is just an indirect way of maintaining a reference
to a U32 node on a per-qdisc basis.

Just add an explicit node pointer for u32 to struct Qdisc an do
away with this global list.

Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -56,6 +56,8 @@ struct Qdisc
 	int			(*reshape_fail)(struct sk_buff *skb,
 					struct Qdisc *q);
 
+	void			*u32_node;
+
 	/* This field is deprecated, but it is still used by CBQ
 	 * and it will live until better solution will be invented.
 	 */