avcodec: fix codec mapping array size check

(cherry picked from commit 99ab06c7ffe189e81118f6122b1661c6c7af033c)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/avcodec/audio.c

@@ -425,7 +425,7 @@ vlc_fourcc_t GetVlcAudioFormat( int fmt )
         [AV_SAMPLE_FMT_FLT]  = VLC_CODEC_FL32,
         [AV_SAMPLE_FMT_DBL]  = VLC_CODEC_FL64,
     };
-    if( sizeof(fcc) / sizeof(fcc[0]) < (unsigned)fmt )
+    if( (sizeof(fcc) / sizeof(fcc[0])) > (unsigned)fmt )
         return fcc[fmt];
     return VLC_CODEC_S16N;
 }