drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/typhoon.c b/drivers/net/typhoon.c
index 0310731..2fb4f97 100644
--- a/drivers/net/typhoon.c
+++ b/drivers/net/typhoon.c
@@ -1241,7 +1241,7 @@
 	ering->tx_pending = TXLO_ENTRIES - 1;
 }
 
-static struct ethtool_ops typhoon_ethtool_ops = {
+static const struct ethtool_ops typhoon_ethtool_ops = {
 	.get_settings		= typhoon_get_settings,
 	.set_settings		= typhoon_set_settings,
 	.get_drvinfo		= typhoon_get_drvinfo,