net: trans_start cleanups

Now that core network takes care of trans_start updates, dont do it
in drivers themselves, if possible. Drivers can avoid one cache miss
(on dev->trans_start) in their start_xmit() handler.

Exceptions are NETIF_F_LLTX drivers

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c
index 65dd502..1e61e6c 100644
--- a/drivers/net/wireless/wl3501_cs.c
+++ b/drivers/net/wireless/wl3501_cs.c
@@ -1307,7 +1307,7 @@
 		printk(KERN_ERR "%s: Error %d resetting card on Tx timeout!\n",
 		       dev->name, rc);
 	else {
-		dev->trans_start = jiffies;
+		dev->trans_start = jiffies; /* prevent tx timeout */
 		netif_wake_queue(dev);
 	}
 }
@@ -1326,7 +1326,6 @@
 
 	spin_lock_irqsave(&this->lock, flags);
 	enabled = wl3501_block_interrupt(this);
-	dev->trans_start = jiffies;
 	rc = wl3501_send_pkt(this, skb->data, skb->len);
 	if (enabled)
 		wl3501_unblock_interrupt(this);