avformat/riff: treat msn audio like gsm_ms

Fixes decoding of 4 files from Ticket2854

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/riff.c

@@ -372,6 +372,7 @@ const AVCodecTag ff_codec_wav_tags[] = {
     { AV_CODEC_ID_ADPCM_YAMAHA,    0x0020 },
     { AV_CODEC_ID_TRUESPEECH,      0x0022 },
     { AV_CODEC_ID_GSM_MS,          0x0031 },
+    { AV_CODEC_ID_GSM_MS,          0x0032 },
     { AV_CODEC_ID_AMR_NB,          0x0038 },  /* rogue format number */
     { AV_CODEC_ID_G723_1,          0x0042 },
     { AV_CODEC_ID_ADPCM_G726,      0x0045 },