rtc: Skip the suspend/resume handling if persistent clock exist

All the RTC suspend and resume functions are to compensate the
sleep time, but this is already done in timekeeping.c if persistent
clock exist.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index f8a0aab..c01773f 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -50,6 +50,10 @@
 	struct rtc_device	*rtc = to_rtc_device(dev);
 	struct rtc_time		tm;
 	struct timespec		delta, delta_delta;
+
+	if (has_persistent_clock())
+		return 0;
+
 	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
 		return 0;
 
@@ -88,6 +92,9 @@
 	struct timespec		new_system, new_rtc;
 	struct timespec		sleep_time;
 
+	if (has_persistent_clock())
+		return 0;
+
 	rtc_hctosys_ret = -ENODEV;
 	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
 		return 0;