SDL_mixer: update dr_mp3.h from mainstream.

SDL Commits
1 
From b3a6fa8b5ad183f0a1bad02527d89a00c3c90106 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 23 Apr 2025 17:21:40 +0300
Subject: [PATCH] update dr_mp3.h from mainstream.

---
 src/codecs/dr_libs/dr_mp3.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/codecs/dr_libs/dr_mp3.h b/src/codecs/dr_libs/dr_mp3.h
index af594ab2..bd0b5750 100644
--- a/src/codecs/dr_libs/dr_mp3.h
+++ b/src/codecs/dr_libs/dr_mp3.h
@@ -2875,6 +2875,7 @@ static drmp3_uint32 drmp3_decode_next_frame_ex__memory(drmp3* pMP3, drmp3d_sampl
         } else if (info.frame_bytes > 0) {
             /* No frames were read, but it looks like we skipped past one. Read the next MP3 frame. */
             pMP3->memory.currentReadPos += (size_t)info.frame_bytes;
+            pMP3->streamCursor          += (size_t)info.frame_bytes;
         } else {
             /* Nothing at all was read. Abort. */
             break;
@@ -2883,7 +2884,7 @@ static drmp3_uint32 drmp3_decode_next_frame_ex__memory(drmp3* pMP3, drmp3d_sampl
 
     /* Consume the data. */
     pMP3->memory.currentReadPos += (size_t)info.frame_bytes;
-    pMP3->streamCursor += (size_t)info.frame_bytes;
+    pMP3->streamCursor          += (size_t)info.frame_bytes;
 
     return pcmFramesRead;
 }