configfs: Constify ct_item_ops in struct config_item_type

Make 'ct_item_ops' const in struct config_item_type.
This allows constification of many structures which hold some function
pointers.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/f43cb57418a7f59e883be8eedc7d6abe802a2094.1761390472.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>

Author: tititiou36

fs/configfs/file.c

@@ -30,7 +30,7 @@ struct configfs_buffer {
 	size_t			count;
 	loff_t			pos;
 	char			* page;
-	struct configfs_item_operations	* ops;
+	const struct configfs_item_operations	*ops;
 	struct mutex		mutex;
 	int			needs_read_fill;
 	bool			read_in_progress;

include/linux/configfs.h

@@ -64,7 +64,7 @@ extern void config_item_put(struct config_item *);
 
 struct config_item_type {
 	struct module				*ct_owner;
-	struct configfs_item_operations		*ct_item_ops;
+	const struct configfs_item_operations	*ct_item_ops;
 	const struct configfs_group_operations	*ct_group_ops;
 	struct configfs_attribute		**ct_attrs;
 	struct configfs_bin_attribute		**ct_bin_attrs;