netdevice hdlc: Convert directly reference of netdev->priv

For killing directly reference of netdev->priv, use netdev->ml_priv to replace it.
Because the private pvc data comes from add_pvc() and can't be allocated in
alloc_netdev().

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Acked-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
index c597696..e960faa 100644
--- a/include/linux/hdlc.h
+++ b/include/linux/hdlc.h
@@ -80,7 +80,7 @@
 
 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
 {
-	return dev->priv;
+	return netdev_priv(dev);
 }
 
 static __inline__ void debug_frame(const struct sk_buff *skb)