drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/3c515.c b/drivers/net/3c515.c
index bde9f5b..91f2232 100644
--- a/drivers/net/3c515.c
+++ b/drivers/net/3c515.c
@@ -379,7 +379,7 @@
 static void update_stats(int addr, struct net_device *dev);
 static struct net_device_stats *corkscrew_get_stats(struct net_device *dev);
 static void set_rx_mode(struct net_device *dev);
-static struct ethtool_ops netdev_ethtool_ops;
+static const struct ethtool_ops netdev_ethtool_ops;
 
 
 /*
@@ -1561,7 +1561,7 @@
 	corkscrew_debug = level;
 }
 
-static struct ethtool_ops netdev_ethtool_ops = {
+static const struct ethtool_ops netdev_ethtool_ops = {
 	.get_drvinfo		= netdev_get_drvinfo,
 	.get_msglevel		= netdev_get_msglevel,
 	.set_msglevel		= netdev_set_msglevel,