net: simplify flags for tx timestamping

This patch removes the abstraction introduced by the union skb_shared_tx in
the shared skb data.

The access of the different union elements at several places led to some
confusion about accessing the shared tx_flags e.g. in skb_orphan_try().

    http://marc.info/?l=linux-netdev&m=128084897415886&w=2

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index ac53bfb..100e43b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1669,17 +1669,13 @@
 
 /**
  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
- * @msg:	outgoing packet
  * @sk:		socket sending this packet
- * @shtx:	filled with instructions for time stamping
+ * @tx_flags:	filled with instructions for time stamping
  *
  * Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
  * parameters are invalid.
  */
-extern int sock_tx_timestamp(struct msghdr *msg,
-			     struct sock *sk,
-			     union skb_shared_tx *shtx);
-
+extern int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
 
 /**
  * sk_eat_skb - Release a skb if it is no longer needed