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/net/ipv4/udp.c b/net/ipv4/udp.c
index 32e0bef..86e757e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -797,7 +797,7 @@
 		return -EOPNOTSUPP;
 
 	ipc.opt = NULL;
-	ipc.shtx.flags = 0;
+	ipc.tx_flags = 0;
 
 	if (up->pending) {
 		/*
@@ -845,7 +845,7 @@
 	ipc.addr = inet->inet_saddr;
 
 	ipc.oif = sk->sk_bound_dev_if;
-	err = sock_tx_timestamp(msg, sk, &ipc.shtx);
+	err = sock_tx_timestamp(sk, &ipc.tx_flags);
 	if (err)
 		return err;
 	if (msg->msg_controllen) {