expo: Drop scene_title_set()

This function is really just an assignment, so serves no useful
purpose. Drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/expo_build.c b/boot/expo_build.c
index 930cc40..d97347e 100644
--- a/boot/expo_build.c
+++ b/boot/expo_build.c
@@ -404,7 +404,7 @@
 	if (ret < 0)
 		return log_msg_ret("tit", ret);
 	title_id = ret;
-	scene_title_set(scn, title_id);
+	scn->title_id = title_id;
 
 	ret = add_txt_str(info, scn_node, scn, "prompt", 0);
 	if (ret < 0)
@@ -420,7 +420,7 @@
 	return 0;
 }
 
-int build_it(struct build_info *info, ofnode root, struct expo **expp)
+static int build_it(struct build_info *info, ofnode root, struct expo **expp)
 {
 	ofnode scenes, node;
 	struct expo *exp;