cpuidle: Add other commits left out during CAF's 3.18 stable merge

These commits were left out by CAF during the 3.18.31 -> 3.18.71 merge,
when they shouldn't have been because they picked clean. Add them back
to avoid future merge conflicts and be closer to stable.

2506cfa ("cpuidle: Fix cpuidle_state_is_coupled() argument in cpuidle_enter()")
887f64e ("cpuidle: Indicate when a device has been unregistered")

Signed-off-by: ahmedradaideh <ahmed.radaideh@gmail.com>
Signed-off-by: khusika <khusikadhamar@gmail.com>

drivers/cpuidle/cpuidle.c

@@ -139,7 +139,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 	/* The cpu is no longer idle or about to enter idle. */
 	sched_idle_set_state(NULL, -1);
 
-	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
+	if (!cpuidle_state_is_coupled(dev, drv, index))
 		local_irq_enable();
 
 	diff = ktime_to_us(ktime_sub(time_end, time_start));
@@ -364,6 +364,8 @@ static void __cpuidle_unregister_device(struct cpuidle_device *dev)
 	list_del(&dev->device_list);
 	per_cpu(cpuidle_devices, dev->cpu) = NULL;
 	module_put(drv->owner);
+
+	dev->registered = 0;
 }
 
 static void __cpuidle_device_init(struct cpuidle_device *dev)