rtc: sh: Mark driver struct with __refdata to prevent section mismatch warning

As described in the added code comment, a reference to .exit.text is ok
for drivers registered via module_platform_driver_probe(). Make this
explicit to prevent a section mismatch warning.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231002080529.2535610-7-u.kleine-koenig@pengutronix.deSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-sh.c

@@ -668,7 +668,13 @@ static const struct of_device_id sh_rtc_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, sh_rtc_of_match);
 
-static struct platform_driver sh_rtc_platform_driver = {
+/*
+ * sh_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver sh_rtc_platform_driver __refdata = {
 	.driver		= {
 		.name	= DRV_NAME,
 		.pm	= &sh_rtc_pm_ops,