ibm_newemac: use free_netdev(netdev) instead of kfree()

Freeing netdev without free_netdev() leads to net, tx leaks.
I might lead to dereferencing freed pointer.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

@@
struct net_device* dev;
@@

-kfree(dev)
+free_netdev(dev)

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ibm_newemac/core.c b/drivers/net/ibm_newemac/core.c
index 3506fd6..519e19e 100644
--- a/drivers/net/ibm_newemac/core.c
+++ b/drivers/net/ibm_newemac/core.c
@@ -2928,7 +2928,7 @@
 	if (dev->emac_irq != NO_IRQ)
 		irq_dispose_mapping(dev->emac_irq);
  err_free:
-	kfree(ndev);
+	free_netdev(ndev);
  err_gone:
 	/* if we were on the bootlist, remove us as we won't show up and
 	 * wake up all waiters to notify them in case they were waiting
@@ -2971,7 +2971,7 @@
 	if (dev->emac_irq != NO_IRQ)
 		irq_dispose_mapping(dev->emac_irq);
 
-	kfree(dev->ndev);
+	free_netdev(dev->ndev);
 
 	return 0;
 }