timekeeping: Move clock sync work to power efficient workqueue

For better use of CPU idle time, allow the scheduler to select the CPU
on which the CMOS clock sync work would be scheduled. This improves
idle residency time and conserver power.

This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected.
Signed-off-by: Shaibal Dutta <shaibal.dutta@broadcom.com>
[zoran.markovic@linaro.org: Added commit message. Aligned code.]
Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1391195904-12497-1-git-send-email-zoran.markovic@linaro.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/ntp.c

@@ -514,12 +514,13 @@ static void sync_cmos_clock(struct work_struct *work)
 		next.tv_sec++;
 		next.tv_nsec -= NSEC_PER_SEC;
 	}
-	schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
+	queue_delayed_work(system_power_efficient_wq,
+			   &sync_cmos_work, timespec_to_jiffies(&next));
 }
 
 void ntp_notify_cmos_timer(void)
 {
-	schedule_delayed_work(&sync_cmos_work, 0);
+	queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
 }
 
 #else