iio: adc: palmas_gpadc: use module_platform_driver to simplify the code

module_platform_driver() makes the code simpler by eliminating
boilerplate code.
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Link: https://lore.kernel.org/r/20200914065401.3726354-1-liushixin2@huawei.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/palmas_gpadc.c

@@ -834,18 +834,7 @@ static struct platform_driver palmas_gpadc_driver = {
 		.of_match_table = of_palmas_gpadc_match_tbl,
 	},
 };
-
-static int __init palmas_gpadc_init(void)
-{
-	return platform_driver_register(&palmas_gpadc_driver);
-}
-module_init(palmas_gpadc_init);
-
-static void __exit palmas_gpadc_exit(void)
-{
-	platform_driver_unregister(&palmas_gpadc_driver);
-}
-module_exit(palmas_gpadc_exit);
+module_platform_driver(palmas_gpadc_driver);
 
 MODULE_DESCRIPTION("palmas GPADC driver");
 MODULE_AUTHOR("Pradeep Goudagunta<pgoudagunta@nvidia.com>");