rtc: set the alarm to the next expiring timer

If there is any non expired timer in the queue, the RTC alarm is never set.
This is an issue when adding a timer that expires before the next non
expired timer.

Ensure the RTC alarm is set in that case.

Fixes: 2b2f5ff0 ("rtc: interface: ignore expired timers when enqueuing new timers")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/interface.c

@@ -779,7 +779,7 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
 	}
 
 	timerqueue_add(&rtc->timerqueue, &timer->node);
-	if (!next) {
+	if (!next || ktime_before(timer->node.expires, next->expires)) {
 		struct rtc_wkalrm alarm;
 		int err;
 		alarm.time = rtc_ktime_to_tm(timer->node.expires);