i40e: never generate both software and hardware timestamps

skb_tx_timestamp() does not report software time stamp
if SKBTX_IN_PROGRESS is set. According to timestamping.txt
software time stamps are a fallback and should not be
generated if hardware time stamp is provided.

Move call to skb_tx_timestamp() after setting
SKBTX_IN_PROGRESS.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -2285,13 +2285,13 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
 	else if (tso)
 		tx_flags |= I40E_TX_FLAGS_TSO;
 
-	skb_tx_timestamp(skb);
-
 	tsyn = i40e_tsyn(tx_ring, skb, tx_flags, &cd_type_cmd_tso_mss);
 
 	if (tsyn)
 		tx_flags |= I40E_TX_FLAGS_TSYN;
 
+	skb_tx_timestamp(skb);
+
 	/* always enable CRC insertion offload */
 	td_cmd |= I40E_TX_DESC_CMD_ICRC;