SDL_mixer: Update android/mpg123.h

From 267a198f96d3b8a41f0b46063e84eda6a2e66f03 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Tue, 13 Dec 2022 23:03:19 +0100
Subject: [PATCH] Update android/mpg123.h

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

diff --git a/external/mpg123 b/external/mpg123
index 5475987f..21471781 160000
--- a/external/mpg123
+++ b/external/mpg123
@@ -1 +1 @@
-Subproject commit 5475987f8fb303daf692f3167f5e81506e3c0dcf
+Subproject commit 21471781893f9a615b1d6ffeab435955a51214c6