module: move 'struct module_use' to internal.h

The struct was moved to the public header file in commit c8e21ce
("module: fix kdb's illicit use of struct module_use.").
Back then the structure was used outside of the module core.
Nowadays this is not true anymore, so the structure can be made internal.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Link: https://lore.kernel.org/r/20250711-kunit-ifdef-modules-v2-1-39443decb1f8@linutronix.de
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>

Author: t-8ch

include/linux/module.h

@@ -313,13 +313,6 @@ void *__symbol_get_gpl(const char *symbol);
 		__used __section(".no_trim_symbol") = __stringify(x); \
 	(typeof(&x))(__symbol_get(__stringify(x))); })
 
-/* modules using other modules: kdb wants to see this. */
-struct module_use {
-	struct list_head source_list;
-	struct list_head target_list;
-	struct module *source, *target;
-};
-
 enum module_state {
 	MODULE_STATE_LIVE,	/* Normal state. */
 	MODULE_STATE_COMING,	/* Full formed, running module_init. */

kernel/module/internal.h

@@ -112,6 +112,13 @@ struct find_symbol_arg {
 	enum mod_license license;
 };
 
+/* modules using other modules */
+struct module_use {
+	struct list_head source_list;
+	struct list_head target_list;
+	struct module *source, *target;
+};
+
 int mod_verify_sig(const void *mod, struct load_info *info);
 int try_to_force_load(struct module *mod, const char *reason);
 bool find_symbol(struct find_symbol_arg *fsa);