driver-core: platform_driver_probe() must probe synchronously

Because platform_driver_probe() checks, after trying to register driver,
if there are any devices that driver successfully bound to, driver's
probe routine must be run synchronously.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>