[NET]: Kill skb->list

Remove the "list" member of struct sk_buff, as it is entirely
redundant.  All SKB list removal callers know which list the
SKB is on, so storing this in sk_buff does nothing other than
taking up some space.

Two tricky bits were SCTP, which I took care of, and two ATM
drivers which Francois Romieu <romieu@fr.zoreil.com> fixed
up.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
diff --git a/net/decnet/dn_nsp_out.c b/net/decnet/dn_nsp_out.c
index 8cce1fd..e0bebf4 100644
--- a/net/decnet/dn_nsp_out.c
+++ b/net/decnet/dn_nsp_out.c
@@ -479,7 +479,7 @@
 		xmit_count = cb2->xmit_count;
 		segnum = cb2->segnum;
 		/* Remove and drop ack'ed packet */
-		skb_unlink(ack);
+		skb_unlink(ack, q);
 		kfree_skb(ack);
 		ack = NULL;