cpuidle: Remove time measurement in poll state

The time measurement is already done in the cpuidle framework in the
'cpuidle_enter_state' function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/driver.c

@@ -182,10 +182,6 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv)
 static int poll_idle(struct cpuidle_device *dev,
 		struct cpuidle_driver *drv, int index)
 {
-	ktime_t	t1, t2;
-	s64 diff;
-
-	t1 = ktime_get();
 	local_irq_enable();
 	if (!current_set_polling_and_test()) {
 		while (!need_resched())
@@ -193,13 +189,6 @@ static int poll_idle(struct cpuidle_device *dev,
 	}
 	current_clr_polling();
 
-	t2 = ktime_get();
-	diff = ktime_to_us(ktime_sub(t2, t1));
-	if (diff > INT_MAX)
-		diff = INT_MAX;
-
-	dev->last_residency = (int) diff;
-
 	return index;
 }