staging/tidspbridge: use module_platform_driver

the code under _init and _exit does platform_driver_register and
platform_driver_unregister respectively only,

so its better to use the module_platform_driver than just replicating
the module_platform_driver's implementation

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