net: constify netdev_class_file

These functions are wrapper arount class_create_file which can take a
const attribute.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 46ff41b..40937ee 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1618,14 +1618,14 @@ int netdev_register_kobject(struct net_device *ndev)
 	return error;
 }
 
-int netdev_class_create_file_ns(struct class_attribute *class_attr,
+int netdev_class_create_file_ns(const struct class_attribute *class_attr,
 				const void *ns)
 {
 	return class_create_file_ns(&net_class, class_attr, ns);
 }
 EXPORT_SYMBOL(netdev_class_create_file_ns);
 
-void netdev_class_remove_file_ns(struct class_attribute *class_attr,
+void netdev_class_remove_file_ns(const struct class_attribute *class_attr,
 				 const void *ns)
 {
 	class_remove_file_ns(&net_class, class_attr, ns);