SDL_mixer: update libmpg123

From a46386f377b61bf8081f76dacb4a4f538844e2e8 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 23 May 2022 17:25:10 +0300
Subject: [PATCH] update libmpg123

---
 external/mpg123 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/mpg123 b/external/mpg123
index a114e482..0b973cd5 160000
--- a/external/mpg123
+++ b/external/mpg123
@@ -1 +1 @@
-Subproject commit a114e482401fdf191bdee4f382c8399d2c242c56
+Subproject commit 0b973cd5d6de30c98d957aade824807d846049ee