e1000: add queue restart counter

Add a netif_wake/start_queue counter to the ethtool statistics to indicated
to the user that their transmit ring could be too small for their workload.

Signed-off-by: Jesse brandeburg <jesse.brandeburg@intel.com>
Cc: Jamal Hadi <hadi@cyberus.ca>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 96e44a8..705e654 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -2974,6 +2974,7 @@
 
 	/* A reprieve! */
 	netif_start_queue(netdev);
+	++adapter->restart_queue;
 	return 0;
 }
 
@@ -3654,8 +3655,10 @@
 		 * sees the new next_to_clean.
 		 */
 		smp_mb();
-		if (netif_queue_stopped(netdev))
+		if (netif_queue_stopped(netdev)) {
 			netif_wake_queue(netdev);
+			++adapter->restart_queue;
+		}
 	}
 
 	if (adapter->detect_tx_hung) {