[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/netfilter/xt_mark.c b/net/netfilter/xt_mark.c
index 934dddf..dfa1ee6 100644
--- a/net/netfilter/xt_mark.c
+++ b/net/netfilter/xt_mark.c
@@ -31,7 +31,7 @@
 {
 	const struct xt_mark_info *info = matchinfo;
 
-	return ((skb->nfmark & info->mask) == info->mark) ^ info->invert;
+	return ((skb->mark & info->mask) == info->mark) ^ info->invert;
 }
 
 static int