drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/wireless/ipw2200.c b/drivers/net/wireless/ipw2200.c
index f29ec0e..7358664 100644
--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -10461,7 +10461,7 @@
 	return 0;
 }
 
-static struct ethtool_ops ipw_ethtool_ops = {
+static const struct ethtool_ops ipw_ethtool_ops = {
 	.get_link = ipw_ethtool_get_link,
 	.get_drvinfo = ipw_ethtool_get_drvinfo,
 	.get_eeprom_len = ipw_ethtool_get_eeprom_len,