[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/sched/cls_u32.c b/net/sched/cls_u32.c
index 0a6cfa0..8b51948 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -143,7 +143,7 @@
 #endif
 
 #ifdef CONFIG_CLS_U32_MARK
-		if ((skb->nfmark & n->mark.mask) != n->mark.val) {
+		if ((skb->mark & n->mark.mask) != n->mark.val) {
 			n = n->next;
 			goto next_knode;
 		} else {