[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/decnet/dn_route.c b/net/decnet/dn_route.c
index 9678b09..2ae35ef 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -77,6 +77,7 @@
 #include <linux/rcupdate.h>
 #include <linux/times.h>
 #include <asm/errno.h>
+#include <net/netlink.h>
 #include <net/neighbour.h>
 #include <net/dst.h>
 #include <net/flow.h>
@@ -1514,7 +1515,7 @@
 
 nlmsg_failure:
 rtattr_failure:
-	skb_trim(skb, b - skb->data);
+	nlmsg_trim(skb, b);
 	return -1;
 }