drivers: rpmsg: class_destroy() is deprecated

The class_destroy() function documents that:

  Note, the pointer to be destroyed must have been created with a call
  to class_create().

However, class_create() is deprecated. rpmsg already uses
class_register() but the class_destroy() calls should also be replaced
with class_unregister().

Link: https://lore.kernel.org/all/2023040244-duffel-pushpin-f738@gregkh/
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20260308140850.1138376-1-jkoolstra@xs4all.nl
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: LATENTBOUNCE

drivers/rpmsg/rpmsg_core.c

@@ -650,7 +650,7 @@ static int __init rpmsg_init(void)
 	ret = bus_register(&rpmsg_bus);
 	if (ret) {
 		pr_err("failed to register rpmsg bus: %d\n", ret);
-		class_destroy(&rpmsg_class);
+		class_unregister(&rpmsg_class);
 	}
 	return ret;
 }
@@ -659,7 +659,7 @@ postcore_initcall(rpmsg_init);
 static void __exit rpmsg_fini(void)
 {
 	bus_unregister(&rpmsg_bus);
-	class_destroy(&rpmsg_class);
+	class_unregister(&rpmsg_class);
 }
 module_exit(rpmsg_fini);