Avcodec/Avformat: fix CODEC_ID_MP2/MP3 issue when using avformat demuxer

This could result in undf codec. Pointed out by ver
(cherry picked from commit 6a30fd81)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/avcodec/fourcc.c

@@ -294,6 +294,7 @@ static const struct
     { VLC_CODEC_DTS, CODEC_ID_DTS, AUDIO_ES },
 
     { VLC_CODEC_MPGA, CODEC_ID_MP3, AUDIO_ES },
+    { VLC_CODEC_MPGA, CODEC_ID_MP2, AUDIO_ES },
 
     { VLC_CODEC_MP4A, CODEC_ID_AAC, AUDIO_ES },
 #if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT( 52, 26, 0 )