net: netdev_kobject_init: annotate with __init

netdev_kobject_init() is only being called from __init context,
that is, net_dev_init(), so annotate it with __init as well, thus
the kernel can take this as a hint that the function is used only
during the initialization phase and free up used memory resources
after its invocation.

Signed-off-by: Daniel Borkmann <dborkman@redhat.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 1a7b7b1..49843bf 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1358,7 +1358,7 @@
 }
 EXPORT_SYMBOL(netdev_class_remove_file_ns);
 
-int netdev_kobject_init(void)
+int __init netdev_kobject_init(void)
 {
 	kobj_ns_type_register(&net_ns_type_operations);
 	return class_register(&net_class);