staging/android: use module_platform_driver

as the init and exit functions just do a platform_driver_register and
platform_driver_unregister, and nothing else, so its better to
use the module_platform_driver macro rather replicating its implementation

Signed-off-by: Devendra Naga <develkernel412222@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>