net: sched: cls_matchall: fix null pointer dereference

Since the head is guaranteed by the check above to be null, the call_rcu
would explode. Remove the previously logically dead code that was made
logically very much alive and kicking.

Fixes: 985538eee06f ("net/sched: remove redundant null check on head")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_matchall.c

@@ -203,7 +203,6 @@ static int mall_change(struct net *net, struct sk_buff *in_skb,
 
 	*arg = (unsigned long) head;
 	rcu_assign_pointer(tp->root, new);
-	call_rcu(&head->rcu, mall_destroy_rcu);
 	return 0;
 
 err_replace_hw_filter: