hwmon: coretemp: update hotplug condition check

Fix two errors in hotplug.  One is for hotplug notifier.  The other is
unnecessary driver unregister.  Because even none of online cpus supports
coretemp, we can't assume new onlined cpu doesn't support it either.  If
related driver is unregistered there we have no chance to use coretemp
from then on.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Huaxu Wan <huaxu.wan@intel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/hwmon/coretemp.c

@@ -502,10 +502,13 @@ static int __cpuinit coretemp_cpu_callback(struct notifier_block *nfb,
 
 	switch (action) {
 	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
 	case CPU_DOWN_FAILED:
+	case CPU_DOWN_FAILED_FROZEN:
 		coretemp_device_add(cpu);
 		break;
 	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
 		coretemp_device_remove(cpu);
 		break;
 	}
@@ -566,7 +569,9 @@ exit_devices_unreg:
 	}
 	mutex_unlock(&pdev_list_mutex);
 exit_driver_unreg:
+#ifndef CONFIG_HOTPLUG_CPU
 	platform_driver_unregister(&coretemp_driver);
+#endif
 exit:
 	return err;
 }