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: 2b2f5ff00f63 ("rtc: interface: ignore expired timers when enqueuing new timers")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 8cec9a0..9eb32ea 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -779,7 +779,7 @@
 	}
 
 	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);