acer-wmi/hp-wmi: use platform_device_unregister instead of platform_device_del in module_exit

platform_device_unregister will also call platform_device_put() to drop reference count.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/acer-wmi.c

@@ -1375,7 +1375,7 @@ static void __exit acer_wmi_exit(void)
 {
 	remove_sysfs(acer_platform_device);
 	remove_debugfs();
-	platform_device_del(acer_platform_device);
+	platform_device_unregister(acer_platform_device);
 	platform_driver_unregister(&acer_platform_driver);
 
 	printk(ACER_INFO "Acer Laptop WMI Extras unloaded\n");

drivers/platform/x86/hp-wmi.c

@@ -760,7 +760,7 @@ static void __exit hp_wmi_exit(void)
 		input_unregister_device(hp_wmi_input_dev);
 	}
 	if (hp_wmi_platform_dev) {
-		platform_device_del(hp_wmi_platform_dev);
+		platform_device_unregister(hp_wmi_platform_dev);
 		platform_driver_unregister(&hp_wmi_driver);
 	}
 }