acerhdf: fix resource reclaim in error path

Fix resource reclaim in below cases:

1. acerhdf_register_platform() does not properly handle
platform_device_alloc() failure and platform_device_add() failure This
patch adds error handing for acerhdf_register_platform().

2. acerhdf_register_platform() return err with acerhdf_dev == NULL.
as a result, acerhdf_unregister_platform() does not do resource reclaim
in acerhdf_init() error path. This patch adds error handing for
acerhdf_register_platform(), thus correct the error handing path in
acerhdf_init(). goto out_err instead of err_unreg if
acerhdf_register_platform() fail.

3. platform_device_del() should only used in error handling. Current
implementation missed a platform_device_put() in acerhdf_exit. This
patch fixes it by using platform_device_unregister() instead of
platform_device_del() in acerhdf_unregister_platform.

Signed-off-by: Axel Lin <[e-mail]>
Acked-by: Peter Feuerer <[e-mail]>
Cc: Matthew Garrett <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Matthew Garrett <[e-mail]>

drivers/platform/x86/acerhdf.c

···
 		return err;
 
 	acerhdf_dev = platform_device_alloc("acerhdf", -1);
-	platform_device_add(acerhdf_dev);
+	if (!acerhdf_dev) {
+		err = -ENOMEM;
+		goto err_device_alloc;
+	}
+	err = platform_device_add(acerhdf_dev);
+	if (err)
+		goto err_device_add;
 
 	return 0;
+
+err_device_add:
+	platform_device_put(acerhdf_dev);
+err_device_alloc:
+	platform_driver_unregister(&acerhdf_driver);
+	return err;
 }
 
 static void acerhdf_unregister_platform(void)
 {
-	if (!acerhdf_dev)
-		return;
-
-	platform_device_del(acerhdf_dev);
+	platform_device_unregister(acerhdf_dev);
 	platform_driver_unregister(&acerhdf_driver);
 }
 
···
 
 	err = acerhdf_register_platform();
 	if (err)
-		goto err_unreg;
+		goto out_err;
 
 	err = acerhdf_register_thermal();
 	if (err)
···
 	acerhdf_unregister_platform();
 
 out_err:
-	return -ENODEV;
+	return err;
 }
 
 static void __exit acerhdf_exit(void)