SDL_mixer: Fixed build warning (5df3a)

SDL Commits
1 
From 5df3aa766b3b24558d6a0cada8a474250e512c5f Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 20 May 2022 11:26:07 -0700
Subject: [PATCH] Fixed build warning

---
 src/mixer.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mixer.c b/src/mixer.c
index c9ce4da1..55325092 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -200,6 +200,8 @@ static int get_loaded_mix_init_flags(void)
             case MUS_OPUS:
                 loaded_init_flags |= MIX_INIT_OPUS;
                 break;
+            default:
+                break;
             }
         }
     }