[IPV6]: Move nfheader_len into rt6_info

The dst member nfheader_len is only used by IPv6.  It's also currently
creating a rather ugly alignment hole in struct dst.  Therefore this patch
moves it from there into struct rt6_info.

It also reorders the fields in rt6_info to minimize holes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1506157..387030d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1099,7 +1099,7 @@
 		sk->sk_sndmsg_page = NULL;
 		sk->sk_sndmsg_off = 0;
 		exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0) -
-			    rt->u.dst.nfheader_len;
+			    rt->nfheader_len;
 		length += exthdrlen;
 		transhdrlen += exthdrlen;
 	} else {
@@ -1114,7 +1114,8 @@
 
 	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
 
-	fragheaderlen = sizeof(struct ipv6hdr) + rt->u.dst.nfheader_len + (opt ? opt->opt_nflen : 0);
+	fragheaderlen = sizeof(struct ipv6hdr) + rt->nfheader_len +
+			(opt ? opt->opt_nflen : 0);
 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
 
 	if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {