hotplug / x86: Fix online state in cpu0 debug interface

_debug_hotplug_cpu() is a debug interface that puts cpu0 offline during
boot-up when CONFIG_DEBUG_HOTPLUG_CPU0 is set.  After cpu0 is put offline
in this interface, however, /sys/devices/system/cpu/cpu0/online still
shows 1 (online).

This patch fixes _debug_hotplug_cpu() to update dev->offline when CPU
online/offline operation succeeded.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Acked-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/x86/kernel/topology.c

@@ -72,16 +72,19 @@ int __ref _debug_hotplug_cpu(int cpu, int action)
 		ret = cpu_down(cpu);
 		if (!ret) {
 			pr_info("CPU %u is now offline\n", cpu);
+			dev->offline = true;
 			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
 		} else
 			pr_debug("Can't offline CPU%d.\n", cpu);
 		break;
 	case 1:
 		ret = cpu_up(cpu);
-		if (!ret)
+		if (!ret) {
+			dev->offline = false;
 			kobject_uevent(&dev->kobj, KOBJ_ONLINE);
-		else
+		} else {
 			pr_debug("Can't online CPU%d.\n", cpu);
+		}
 		break;
 	default:
 		ret = -EINVAL;