input: fix incompatible-pointer-types assignment

Fixes #28441

src/input/input_internal.h

@@ -117,7 +117,7 @@ typedef struct input_thread_private_t
 
     /* Title infos FIXME multi-input (not easy) ? */
     int          i_title;
-    const input_title_t **title;
+    input_title_t * const *title;
 
     int i_title_offset;
     int i_seekpoint_offset;