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/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 90d82b3..ff954b3 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -135,7 +135,10 @@
 
 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 
-static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
+static const struct ppp_channel_ops pppol2tp_chan_ops = {
+	.start_xmit =  pppol2tp_xmit,
+};
+
 static const struct proto_ops pppol2tp_ops;
 
 /* Helpers to obtain tunnel/session contexts from sockets.