[SK_BUFF]: Use the helpers to get the layer header pointer

Some more cases...

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 11ab100..11a6ac7 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -601,7 +601,7 @@
 		/*
 		 *	Copy a block of the IP datagram.
 		 */
-		if (skb_copy_bits(skb, ptr, skb2->h.raw, len))
+		if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
 			BUG();
 		left -= len;