[NET]: Turn nfmark into generic mark

nfmark is being used in various subsystems and has become
the defacto mark field for all kinds of packets. Therefore
it makes sense to rename it to `mark' and remove the
dependency on CONFIG_NETFILTER.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 9333068..1bde3ac 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -499,12 +499,12 @@
 	dst_release(to->dst);
 	to->dst = dst_clone(from->dst);
 	to->dev = from->dev;
+	to->mark = from->mark;
 
 #ifdef CONFIG_NET_SCHED
 	to->tc_index = from->tc_index;
 #endif
 #ifdef CONFIG_NETFILTER
-	to->nfmark = from->nfmark;
 	/* Connection association is same as pre-frag packet */
 	nf_conntrack_put(to->nfct);
 	to->nfct = from->nfct;