PM / QoS: Add pm_qos_update_target/flags tracepoints

This patch adds tracepoints to pm_qos_update_target and
pm_qos_update_flags. It's useful for checking pm qos action,
previous value and current value.

Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index f2f5f6e..4fb8d14 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -44,6 +44,7 @@
 
 #include <linux/uaccess.h>
 #include <linux/export.h>
+#include <trace/events/power.h>
 
 /*
  * locking rule: all changes to constraints or notifiers lists
@@ -202,6 +203,7 @@
 
 	spin_unlock_irqrestore(&pm_qos_lock, flags);
 
+	trace_pm_qos_update_target(action, prev_value, curr_value);
 	if (prev_value != curr_value) {
 		blocking_notifier_call_chain(c->notifiers,
 					     (unsigned long)curr_value,
@@ -272,6 +274,7 @@
 
 	spin_unlock_irqrestore(&pm_qos_lock, irqflags);
 
+	trace_pm_qos_update_flags(action, prev_value, curr_value);
 	return prev_value != curr_value;
 }