drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/wireless/ipw2100.c b/drivers/net/wireless/ipw2100.c
index d2db8eb..b4d81a0 100644
--- a/drivers/net/wireless/ipw2100.c
+++ b/drivers/net/wireless/ipw2100.c
@@ -5911,7 +5911,7 @@
 	return (priv->status & STATUS_ASSOCIATED) ? 1 : 0;
 }
 
-static struct ethtool_ops ipw2100_ethtool_ops = {
+static const struct ethtool_ops ipw2100_ethtool_ops = {
 	.get_link = ipw2100_ethtool_get_link,
 	.get_drvinfo = ipw_ethtool_get_drvinfo,
 };