[NETLINK]: Use nlmsg_trim() where appropriate

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_rsvp.h b/net/sched/cls_rsvp.h
index 87ed6f3..22f9ede 100644
--- a/net/sched/cls_rsvp.h
+++ b/net/sched/cls_rsvp.h
@@ -630,7 +630,7 @@
 	return skb->len;
 
 rtattr_failure:
-	skb_trim(skb, b - skb->data);
+	nlmsg_trim(skb, b);
 	return -1;
 }