sch_cake: Fix tin order when set through skb->priority

In diffserv mode, CAKE stores tins in a different order internally than
the logical order exposed to userspace. The order remapping was missing
in the handling of 'tc filter' priority mappings through skb->priority,
resulting in bulk and best effort mappings being reversed relative to
how they are displayed.

Fix this by adding the missing mapping when reading skb->priority.

Fixes: 83f8fd69 ("sch_cake: Add DiffServ handling")
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_cake.c

@@ -1546,7 +1546,7 @@ static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
 	if (TC_H_MAJ(skb->priority) == sch->handle &&
 	    TC_H_MIN(skb->priority) > 0 &&
 	    TC_H_MIN(skb->priority) <= q->tin_cnt) {
-		tin = TC_H_MIN(skb->priority) - 1;
+		tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
 
 		if (q->rate_flags & CAKE_FLAG_WASH)
 			cake_wash_diffserv(skb);