net/sched: fix pointer check in gen_handle

Fixes sparse warning about pointer in gen_handle:
net/sched/cls_rsvp.h:392:40: warning: Using plain integer as NULL pointer

Fixes: 8113c095672f6 ("net_sched: use void pointer for filter handle")
Signed-off-by: Josh Hunt <johunt@akamai.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_rsvp.h

@@ -389,7 +389,7 @@ static unsigned int gen_handle(struct tcf_proto *tp, unsigned salt)
 		if ((data->hgenerator += 0x10000) == 0)
 			data->hgenerator = 0x10000;
 		h = data->hgenerator|salt;
-		if (rsvp_get(tp, h) == 0)
+		if (!rsvp_get(tp, h))
 			return h;
 	}
 	return 0;