[INET]: Give outer DSCP directly to ip*_copy_dscp

This patch changes the prototype of ipv4_copy_dscp and ipv6_copy_dscp so
that they directly take the outer DSCP rather than the outer IP header.
This will help us to unify the code for inter-family tunnels.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index e4deecb..68a9f56 100644
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -113,7 +113,7 @@
 	iph = ip_hdr(skb);
 	if (iph->protocol == IPPROTO_IPIP) {
 		if (x->props.flags & XFRM_STATE_DECAP_DSCP)
-			ipv4_copy_dscp(iph, ipip_hdr(skb));
+			ipv4_copy_dscp(ipv4_get_dsfield(iph), ipip_hdr(skb));
 		if (!(x->props.flags & XFRM_STATE_NOECN))
 			ipip_ecn_decapsulate(skb);
 	}