drivers/net: const-ify ethtool_ops declarations

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
index de8da82..6d71bea 100644
--- a/drivers/net/gianfar_ethtool.c
+++ b/drivers/net/gianfar_ethtool.c
@@ -567,7 +567,7 @@
 }
 
 
-struct ethtool_ops gfar_ethtool_ops = {
+const struct ethtool_ops gfar_ethtool_ops = {
 	.get_settings = gfar_gsettings,
 	.set_settings = gfar_ssettings,
 	.get_drvinfo = gfar_gdrvinfo,