gpio: vf610: use builtin_platform_driver

Use builtin_platform_driver() helper to simplify the code.

Signed-off-by: Geliang Tang <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-vf610.c

···
 	.probe		= vf610_gpio_probe,
 };
 
-static int __init gpio_vf610_init(void)
-{
-	return platform_driver_register(&vf610_gpio_driver);
-}
-device_initcall(gpio_vf610_init);
+builtin_platform_driver(vf610_gpio_driver);