power: reset: msm: use builtin_platform_driver() to simplify code

The msm_restart_init() doesn't do anything special, so it can use the
builtin_platform_driver() macro to eliminate boilerplate code.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230807131951.3443880-3-yangyingliang@huawei.comSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/msm-poweroff.c

@@ -59,9 +59,4 @@ static struct platform_driver msm_restart_driver = {
 		.of_match_table = of_match_ptr(of_msm_restart_match),
 	},
 };
-
-static int __init msm_restart_init(void)
-{
-	return platform_driver_register(&msm_restart_driver);
-}
-device_initcall(msm_restart_init);
+builtin_platform_driver(msm_restart_driver);