unicore32: pwm: Use module_platform_driver()

Some of the boilerplate code can be eliminated by using this macro. The
driver was previously registered with an arch_initcall(), so technically
this is no longer the same, but when the driver is moved to the PWM
framework, deferred probing will take care of any driver probe ordering
issues.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Qin Rui <qinrui@mprc.pku.edu.cn>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>

arch/unicore32/kernel/pwm.c

@@ -254,25 +254,6 @@ static struct platform_driver puv3_pwm_driver = {
 	.probe		= puv3_pwm_probe,
 	.remove		= __devexit_p(pwm_remove),
 };
-
-static int __init pwm_init(void)
-{
-	int ret = 0;
-
-	ret = platform_driver_register(&puv3_pwm_driver);
-	if (ret) {
-		printk(KERN_ERR "failed to register puv3_pwm_driver\n");
-		return ret;
-	}
-
-	return ret;
-}
-arch_initcall(pwm_init);
-
-static void __exit pwm_exit(void)
-{
-	platform_driver_unregister(&puv3_pwm_driver);
-}
-module_exit(pwm_exit);
+module_platform_driver(puv3_pwm_driver);
 
 MODULE_LICENSE("GPL v2");