net: dsa: ocelot: Constify dsa_device_ops

ocelot_netdev_ops should be const since that is what the DSA layer
expects.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/tag_ocelot.c

@@ -228,7 +228,7 @@ static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
 	return skb;
 }
 
-static struct dsa_device_ops ocelot_netdev_ops = {
+static const struct dsa_device_ops ocelot_netdev_ops = {
 	.name			= "ocelot",
 	.proto			= DSA_TAG_PROTO_OCELOT,
 	.xmit			= ocelot_xmit,