drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/wireless/hostap/hostap_ioctl.c b/drivers/net/wireless/hostap/hostap_ioctl.c
index 8399de5..7a49785 100644
--- a/drivers/net/wireless/hostap/hostap_ioctl.c
+++ b/drivers/net/wireless/hostap/hostap_ioctl.c
@@ -3908,7 +3908,7 @@
 		 local->sta_fw_ver & 0xff);
 }
 
-struct ethtool_ops prism2_ethtool_ops = {
+const struct ethtool_ops prism2_ethtool_ops = {
 	.get_drvinfo = prism2_get_drvinfo
 };