[NET]: Fix TX timeout regression in Intel drivers.

This fixes a regression added by changeset
53e52c729cc169db82a6105fac7a166e10c2ec36 ("[NET]: Make ->poll()
breakout consistent in Intel ethernet drivers.")

As pointed out by Jesse Brandeburg, for three of the drivers edited
above there is breakout logic in the *_clean_tx_irq() code to prevent
running TX reclaim forever.  If this occurs, we have to elide NAPI
poll completion or else those TX events will never be serviced.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 13d57b0..0c9a6f7 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3919,7 +3919,7 @@
 {
 	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
 	struct net_device *poll_dev = adapter->netdev;
-	int work_done = 0;
+	int tx_cleaned = 0, work_done = 0;
 
 	/* Must NOT use netdev_priv macro here. */
 	adapter = poll_dev->priv;
@@ -3929,14 +3929,17 @@
 	 * simultaneously.  A failure obtaining the lock means
 	 * tx_ring[0] is currently being cleaned anyway. */
 	if (spin_trylock(&adapter->tx_queue_lock)) {
-		e1000_clean_tx_irq(adapter,
-				   &adapter->tx_ring[0]);
+		tx_cleaned = e1000_clean_tx_irq(adapter,
+						&adapter->tx_ring[0]);
 		spin_unlock(&adapter->tx_queue_lock);
 	}
 
 	adapter->clean_rx(adapter, &adapter->rx_ring[0],
 	                  &work_done, budget);
 
+	if (tx_cleaned)
+		work_done = budget;
+
 	/* If budget not fully consumed, exit the polling mode */
 	if (work_done < budget) {
 		if (likely(adapter->itr_setting & 3))