[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_fw.c b/net/sched/cls_fw.c
index f5f3558..bbec4a0 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -38,6 +38,7 @@
 #include <linux/notifier.h>
 #include <linux/netfilter.h>
 #include <net/ip.h>
+#include <net/netlink.h>
 #include <net/route.h>
 #include <linux/skbuff.h>
 #include <net/sock.h>
@@ -382,7 +383,7 @@
 	return skb->len;
 
 rtattr_failure:
-	skb_trim(skb, b - skb->data);
+	nlmsg_trim(skb, b);
 	return -1;
 }