cpmac: prevent fatal exception in cpmac_end_xmit

We should not be stopping the subqueues in cpmac_end_xmit
but rather test the status of them. Replace the calls to
netif_subqueue_stop by __netif_subqueue_stopped. This
fixes an unrecoverable exception from happening when
running the driver.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/cpmac.c

@@ -615,13 +615,13 @@ static void cpmac_end_xmit(struct net_device *dev, int queue)
 
 		dev_kfree_skb_irq(desc->skb);
 		desc->skb = NULL;
-		if (netif_subqueue_stopped(dev, queue))
+		if (__netif_subqueue_stopped(dev, queue))
 			netif_wake_subqueue(dev, queue);
 	} else {
 		if (netif_msg_tx_err(priv) && net_ratelimit())
 			printk(KERN_WARNING
 			       "%s: end_xmit: spurious interrupt\n", dev->name);
-		if (netif_subqueue_stopped(dev, queue))
+		if (__netif_subqueue_stopped(dev, queue))
 			netif_wake_subqueue(dev, queue);
 	}
 }