expo: Export scene_menuitem_find() for use in internal code

Make this function available to other expo code so we can use it to look
up a menu item.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/scene_internal.h b/boot/scene_internal.h
index 60b1434..23e29cb 100644
--- a/boot/scene_internal.h
+++ b/boot/scene_internal.h
@@ -222,4 +222,16 @@
 int expo_iter_scene_objs(struct expo *exp, expo_scene_obj_iterator iter,
 			 void *priv);
 
+/**
+ * scene_menuitem_find() - Find the menu item for an ID
+ *
+ * Looks up the menu to find the item with the given ID
+ *
+ * @menu: Menu to check
+ * @id: ID to look for
+ * Return: Menu item, or NULL if not found
+ */
+struct scene_menitem *scene_menuitem_find(const struct scene_obj_menu *menu,
+					  int id);
+
 #endif /* __SCENE_INTERNAL_H */
diff --git a/boot/scene_menu.c b/boot/scene_menu.c
index 57ffb52..602fe24 100644
--- a/boot/scene_menu.c
+++ b/boot/scene_menu.c
@@ -33,8 +33,8 @@
 		scene_menuitem_destroy(item);
 }
 
-static struct scene_menitem *scene_menuitem_find(struct scene_obj_menu *menu,
-						 int id)
+struct scene_menitem *scene_menuitem_find(const struct scene_obj_menu *menu,
+					  int id)
 {
 	struct scene_menitem *item;