lib : kobject: fix refcount imblance on kobject_rename

the kobj refcount increased by kobject_get should be released before
error return, otherwise lead to a memory leak.
Signed-off-by: Lin Yi <teroincn@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/kobject.c

@@ -498,8 +498,10 @@ int kobject_rename(struct kobject *kobj, const char *new_name)
 	kobj = kobject_get(kobj);
 	if (!kobj)
 		return -EINVAL;
-	if (!kobj->parent)
+	if (!kobj->parent) {
+		kobject_put(kobj);
 		return -EINVAL;
+	}
 
 	devpath = kobject_get_path(kobj, GFP_KERNEL);
 	if (!devpath) {