expo: Drop unneceesary calls to expo_str()

The scene_txt_str() function calls expo_str() so there is no need to
call it beforehand. Drop this unnecessary code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/expo_build.c b/boot/expo_build.c
index fece3ea..930cc40 100644
--- a/boot/expo_build.c
+++ b/boot/expo_build.c
@@ -46,7 +46,6 @@
 		const char *find_name, uint obj_id)
 {
 	const char *text;
-	uint str_id;
 	int ret;
 
 	info->err_prop = find_name;
@@ -67,14 +66,9 @@
 			return log_msg_ret("id", -EINVAL);
 	}
 
-	ret = expo_str(scn->expo, find_name, 0, text);
+	ret = scene_txt_str(scn, find_name, obj_id, 0, text, NULL);
 	if (ret < 0)
 		return log_msg_ret("add", ret);
-	str_id = ret;
-
-	ret = scene_txt_str(scn, find_name, obj_id, str_id, text, NULL);
-	if (ret < 0)
-		return log_msg_ret("add", ret);
 
 	return ret;
 }
@@ -94,7 +88,6 @@
 		     const char *find_name, int index, uint obj_id)
 {
 	const char *text;
-	uint str_id;
 	int ret;
 
 	ret = ofnode_read_string_index(node, find_name, index, &text);
@@ -114,12 +107,7 @@
 			return log_msg_ret("id", -EINVAL);
 	}
 
-	ret = expo_str(scn->expo, find_name, 0, text);
-	if (ret < 0)
-		return log_msg_ret("add", ret);
-	str_id = ret;
-
-	ret = scene_txt_str(scn, find_name, obj_id, str_id, text, NULL);
+	ret = scene_txt_str(scn, find_name, obj_id, 0, text, NULL);
 	if (ret < 0)
 		return log_msg_ret("add", ret);