driver core: class: make class_register() take a const *

Now that the class code is cleaned up to not modify the class pointer
registered with it, change class_register() to take a const * to allow
the structure to be placed into read-only memory.

Acked-by: Rafael J. Wysocki <[e-mail]>
Link: https://lore.kernel.org/r/2023040248-customary-release-4aec@gregkh
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/base/base.h

···
 	struct device *dev_root;
 
 	struct kset glue_dirs;
-	struct class *class;
+	const struct class *class;
 
 	struct lock_class_key lock_key;
 };

drivers/base/class.c

···
 static void class_release(struct kobject *kobj)
 {
 	struct subsys_private *cp = to_subsys_private(kobj);
-	struct class *class = cp->class;
+	const struct class *class = cp->class;
 
 	pr_debug("class '%s': release.\n", class->name);
 
···
 static const struct kobj_ns_type_operations *class_child_ns_type(const struct kobject *kobj)
 {
 	const struct subsys_private *cp = to_subsys_private(kobj);
-	struct class *class = cp->class;
+	const struct class *class = cp->class;
 
 	return class->ns_type;
 }
···
 	put_device(dev);
 }
 
-int class_register(struct class *cls)
+int class_register(const struct class *cls)
 {
 	struct subsys_private *cp;
 	struct lock_class_key *key;

include/linux/device/class.h

···
 	const struct device_type	*type;
 };
 
-int __must_check class_register(struct class *class);
+int __must_check class_register(const struct class *class);
 void class_unregister(const struct class *class);
 bool class_is_registered(const struct class *class);