rtc: disable hpet emulation on suspend

I noticed that rtc wont generate interrupts after a resume from disk.
Here hpet rtc emulation is used.

Problem is that rtc hpet comparator, isn't reinitialized after resume.
Easiest way to solve this, is always mask all hpet interrupts on suspend
This is triggered, when suspending with alarm set.

Otherwise, hpet driver will think it doesn't need to reinitialize
the rtc comparator, thus rtc interrupts won't work.

This emulation isn't need for wakealarm.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-cmos.c

@@ -871,8 +871,9 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg)
 			mask = RTC_IRQMASK;
 		tmp &= ~mask;
 		CMOS_WRITE(tmp, RTC_CONTROL);
-		hpet_mask_rtc_irq_bit(mask);
 
+		/* shut down hpet emulation - we don't need it for alarm */
+		hpet_mask_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
 		cmos_checkintr(cmos, tmp);
 	}
 	spin_unlock_irq(&rtc_lock);