driver core: class: make class_for_each_device() options const

class_for_each_device() does not modify the struct class or the struct
device passed into it, so mark them as const * to enforce that.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-6-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/class.c

@@ -355,7 +355,7 @@ EXPORT_SYMBOL_GPL(class_dev_iter_exit);
  * @fn is allowed to do anything including calling back into class
  * code.  There's no locking restriction.
  */
-int class_for_each_device(struct class *class, struct device *start,
+int class_for_each_device(const struct class *class, const struct device *start,
 			  void *data, int (*fn)(struct device *, void *))
 {
 	struct class_dev_iter iter;

include/linux/device/class.h

@@ -109,7 +109,7 @@ extern void class_dev_iter_init(struct class_dev_iter *iter,
 extern struct device *class_dev_iter_next(struct class_dev_iter *iter);
 extern void class_dev_iter_exit(struct class_dev_iter *iter);
 
-extern int class_for_each_device(struct class *class, struct device *start,
+extern int class_for_each_device(const struct class *class, const struct device *start,
 				 void *data,
 				 int (*fn)(struct device *dev, void *data));
 extern struct device *class_find_device(struct class *class,