power: reset: at91-poweroff: Stop using module_platform_driver_probe()

On today's platforms the benefit of platform_driver_probe() isn't that
relevant any more. It allows to drop some code after booting (or module
loading) for .probe() and discard the .remove() function completely if
the driver is built-in. This typically saves a few 100k.

The downside of platform_driver_probe() is that the driver cannot be
bound and unbound at runtime which is ancient and so slightly
complicates testing. There are also thoughts to deprecate
platform_driver_probe() because it adds some complexity in the driver
core for little gain. Also many drivers don't use it correctly. This
driver for example misses to mark the driver struct with __ref which is
needed to suppress a (W=1) modpost warning.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Link: https://lore.kernel.org/r/20231104211501.3676352-17-u.kleine-koenig@pengutronix.de
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/at91-poweroff.c

@@ -149,7 +149,7 @@ static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
 	writel(wakeup_mode | mode, at91_shdwc.shdwc_base + AT91_SHDW_MR);
 }
 
-static int __init at91_poweroff_probe(struct platform_device *pdev)
+static int at91_poweroff_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
 	u32 ddr_type;
@@ -202,7 +202,7 @@ static int __init at91_poweroff_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int __exit at91_poweroff_remove(struct platform_device *pdev)
+static int at91_poweroff_remove(struct platform_device *pdev)
 {
 	if (pm_power_off == at91_poweroff)
 		pm_power_off = NULL;
@@ -224,13 +224,14 @@ static const struct of_device_id at91_poweroff_of_match[] = {
 MODULE_DEVICE_TABLE(of, at91_poweroff_of_match);
 
 static struct platform_driver at91_poweroff_driver = {
-	.remove = __exit_p(at91_poweroff_remove),
+	.probe = at91_poweroff_probe,
+	.remove = at91_poweroff_remove,
 	.driver = {
 		.name = "at91-poweroff",
 		.of_match_table = at91_poweroff_of_match,
 	},
 };
-module_platform_driver_probe(at91_poweroff_driver, at91_poweroff_probe);
+module_platform_driver(at91_poweroff_driver);
 
 MODULE_AUTHOR("Atmel Corporation");
 MODULE_DESCRIPTION("Shutdown driver for Atmel SoCs");