rtc: interface: silence KMSAN warning

KMSAN complains that alarm->time can be used uninitialized. Pass 0 to
trace_rtc_read_alarm in case it has not been set.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: alexandrebelloni

drivers/rtc/interface.c

@@ -205,7 +205,7 @@ static int rtc_read_alarm_internal(struct rtc_device *rtc,
 
 	mutex_unlock(&rtc->ops_lock);
 
-	trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
+	trace_rtc_read_alarm(err?0:rtc_tm_to_time64(&alarm->time), err);
 	return err;
 }