Add speex tag to nsv_codec_audio_tags.

Originally committed as revision 18604 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/nsvdec.c

@@ -207,6 +207,7 @@ static const AVCodecTag nsv_codec_audio_tags[] = {
     { CODEC_ID_MP3, MKTAG('M', 'P', '3', ' ') },
     { CODEC_ID_AAC, MKTAG('A', 'A', 'C', ' ') },
     { CODEC_ID_AAC, MKTAG('A', 'A', 'C', 'P') }, /* _CUTTED__MUXED_2 Heads - Out Of The City.nsv */
+    { CODEC_ID_SPEEX, MKTAG('S', 'P', 'X', ' ') },
     { CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
     { 0, 0 },
 };