net: sched: fix error return code in tcf_del_walker()

When nla_put_u32() fails, 'ret' could be 0, it should
return error code in tcf_del_walker().

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Yang Yingliang <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/sched/act_api.c

···
 	}
 	mutex_unlock(&idrinfo->lock);
 
-	if (nla_put_u32(skb, TCA_FCNT, n_i))
+	ret = nla_put_u32(skb, TCA_FCNT, n_i);
+	if (ret)
 		goto nla_put_failure;
 	nla_nest_end(skb, nest);