lpc_eth: fix tx completion

__lpc_handle_xmit() has two bugs :

1) It can leak skbs in case TXSTATUS_ERROR is set

2) It can wake up txqueue while no slot was freed.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NRoland Stigge <stigge@antcom.de>
Tested-by: NRoland Stigge <stigge@antcom.de>
Cc: Kevin Wells <kevin.wells@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/nxp/lpc_eth.c

@@ -946,16 +946,16 @@ static void __lpc_handle_xmit(struct net_device *ndev)
 			/* Update stats */
 			ndev->stats.tx_packets++;
 			ndev->stats.tx_bytes += skb->len;
-
-			/* Free buffer */
-			dev_kfree_skb_irq(skb);
 		}
+		dev_kfree_skb_irq(skb);
 
 		txcidx = readl(LPC_ENET_TXCONSUMEINDEX(pldat->net_base));
 	}
 
+	if (pldat->num_used_tx_buffs <= ENET_TX_DESC/2) {
 		if (netif_queue_stopped(ndev))
 			netif_wake_queue(ndev);
+	}
 }
 
 static int __lpc_handle_recv(struct net_device *ndev, int budget)