rtc: enforce rtc_timer_init private_data type

All the remaining users of rtc_timers are passing the rtc_device as private
data. Enforce that and rename private_data to rtc.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 6d36408..8d9b65d 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -178,9 +178,9 @@
 	timerqueue_init_head(&rtc->timerqueue);
 	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
 	/* Init aie timer */
-	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
+	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc);
 	/* Init uie timer */
-	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
+	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
 	/* Init pie timer */
 	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	rtc->pie_timer.function = rtc_pie_update_irq;