Revert "alarmtimer: Check RTC features instead of ops"

This reverts commit 3599aef557044f5572cc1e9b409f10012726e14b which is
commit e09784a8a751e539dffc94d43bc917b0ac1e934a upstream.

It breaks the Android kernel build and can be brought back in the future
in a safe way if it is really needed.

Bug: 161946584
Change-Id: I598118405dba96bbb080d2b1381768e2053eb969
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

kernel/time/alarmtimer.c

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 976974e..771b310 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -92,7 +92,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
 	if (rtcdev)
 		return -EBUSY;
 
-	if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+	if (!rtc->ops->set_alarm)
 		return -1;
 	if (!device_may_wakeup(rtc->dev.parent))
 		return -1;