ppp: make channel_ops const

The PPP channel ops structure should be const.
Cleanup the declarations to use standard C99 format.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ppp_channel.h b/include/linux/ppp_channel.h
index bff98ec..5d87f81 100644
--- a/include/linux/ppp_channel.h
+++ b/include/linux/ppp_channel.h
@@ -36,7 +36,7 @@
 
 struct ppp_channel {
 	void		*private;	/* channel private data */
-	struct ppp_channel_ops *ops;	/* operations for this channel */
+	const struct ppp_channel_ops *ops; /* operations for this channel */
 	int		mtu;		/* max transmit packet size */
 	int		hdrlen;		/* amount of headroom channel needs */
 	void		*ppp;		/* opaque to channel */