kobject: get rid of kobject_add_dir

kobject_create_and_add is the same as kobject_add_dir, so drop
kobject_add_dir.


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index c8f2ac0..992eba3 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -562,7 +562,8 @@
 	static struct kobject *virtual_dir = NULL;
 
 	if (!virtual_dir)
-		virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual");
+		virtual_dir = kobject_create_and_add("virtual",
+						     &devices_subsys.kobj);
 
 	return virtual_dir;
 }