SDL: Fixed SDL_ConvertMonoToStereo_SSE reading out of bounds

SDL Commits
1 
From 1ee28323266dfba37fb4655eddddb338acc7863c Mon Sep 17 00:00:00 2001
From: Brick <[EMAIL REDACTED]>
Date: Sun, 30 Apr 2023 17:55:01 +0100
Subject: [PATCH] Fixed SDL_ConvertMonoToStereo_SSE reading out of bounds

---
 src/audio/SDL_audiocvt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/audio/SDL_audiocvt.c b/src/audio/SDL_audiocvt.c
index 5880c8bf8471..28f3b203882e 100644
--- a/src/audio/SDL_audiocvt.c
+++ b/src/audio/SDL_audiocvt.c
@@ -189,8 +189,8 @@ static void SDL_TARGETING("sse") SDL_ConvertMonoToStereo_SSE(float *dst, const f
     int i = num_frames;
 
     /* convert backwards, since output is growing in-place. */
-    src += (num_frames-1) * 1;
-    dst += (num_frames-1) * 2;
+    src += (num_frames-4) * 1;
+    dst += (num_frames-4) * 2;
 
     LOG_DEBUG_AUDIO_CONVERT("mono", "stereo (using SSE)");