pinctrl: sprd: use module_platform_driver to simplify the code

module_platform_driver() makes the code simpler by eliminating
boilerplate code.

Signed-off-by: Liu Shixin <[e-mail]>
Acked-by: Chunyan Zhang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/sprd/pinctrl-sprd-sc9860.c

···
 	.remove = sprd_pinctrl_remove,
 	.shutdown = sprd_pinctrl_shutdown,
 };
-
-static int sprd_pinctrl_init(void)
-{
-	return platform_driver_register(&sprd_pinctrl_driver);
-}
-module_init(sprd_pinctrl_init);
-
-static void sprd_pinctrl_exit(void)
-{
-	platform_driver_unregister(&sprd_pinctrl_driver);
-}
-module_exit(sprd_pinctrl_exit);
+module_platform_driver(sprd_pinctrl_driver);
 
 MODULE_DESCRIPTION("SPREADTRUM Pin Controller Driver");
 MODULE_AUTHOR("Baolin Wang <[e-mail]>");