[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>

include/linux/skbuff.h

@@ -216,7 +216,7 @@ enum {
  *	@tail: Tail pointer
  *	@end: End pointer
  *	@destructor: Destruct function
- *	@nfmark: Can be used for communication between hooks
+ *	@mark: Generic packet mark
  *	@nfct: Associated connection, if any
  *	@ipvs_property: skbuff is owned by ipvs
  *	@nfctinfo: Relationship of this skb to the connection
@@ -295,7 +295,6 @@ struct sk_buff {
 #ifdef CONFIG_BRIDGE_NETFILTER
 	struct nf_bridge_info	*nf_bridge;
 #endif
-	__u32			nfmark;
 #endif /* CONFIG_NETFILTER */
 #ifdef CONFIG_NET_SCHED
 	__u16			tc_index;	/* traffic control index */
@@ -310,6 +309,7 @@ struct sk_buff {
 	__u32			secmark;
 #endif
 
+	__u32			mark;
 
 	/* These elements must be at the end, see alloc_skb() for details.  */
 	unsigned int		truesize;