drivers/rtc/rtc-cmos.c: don't disable hpet emulation on suspend

There's a bug where rtc alarms are ignored after the rtc cmos suspends
but before the system finishes suspend.  Since hpet emulation is
disabled and it still handles the interrupts, a wake event is never
registered which is done from the rtc layer.

This patch reverts commit d1b2efa83fbf ("rtc: disable hpet emulation on
suspend") which disabled hpet emulation.  To fix the problem mentioned
in that commit, hpet_rtc_timer_init() is called directly on resume.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-cmos.c

@@ -804,9 +804,8 @@ static int cmos_suspend(struct device *dev)
 			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);
@@ -870,6 +869,7 @@ static int cmos_resume(struct device *dev)
 			rtc_update_irq(cmos->rtc, 1, mask);
 			tmp &= ~RTC_AIE;
 			hpet_mask_rtc_irq_bit(RTC_AIE);
+			hpet_rtc_timer_init();
 		} while (mask & RTC_AIE);
 		spin_unlock_irq(&rtc_lock);
 	}