staging/phison: use module_pci_driver macro

remove the duplication of module_pci_driver and use this macro instead

module_pci_driver macro does the same things as the code below does

static int __init pci_test_dev_init(void)
{
       return pci_register_driver(&pci_test_driver_ops);
}

static void __exit pci_test_dev_exit(void)
{
       pci_unregister_driver(&pci_test_driver_ops);
}

module_init(pci_test_dev_init);
module_exit(pci_test_dev_exit);

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