driver core: don't initialize 'parent' in device_add()

'parent' is always overwritten before getting used and there is no need
to initialize it with NULL.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/core.c

@@ -1607,7 +1607,7 @@ int device_private_init(struct device *dev)
  */
 int device_add(struct device *dev)
 {
-	struct device *parent = NULL;
+	struct device *parent;
 	struct kobject *kobj;
 	struct class_interface *class_intf;
 	int error = -EINVAL;