lavf/matroska: Fix the codec_id for mkv tag A_MPEG/L1.

When the mapping was originally added AV_CODEC_ID_MP1 did not exist.

libavformat/matroska.c

@@ -35,7 +35,7 @@ const CodecTags ff_mkv_codec_tags[]={
     {"A_FLAC"           , AV_CODEC_ID_FLAC},
     {"A_MLP"            , AV_CODEC_ID_MLP},
     {"A_MPEG/L2"        , AV_CODEC_ID_MP2},
-    {"A_MPEG/L1"        , AV_CODEC_ID_MP2},
+    {"A_MPEG/L1"        , AV_CODEC_ID_MP1},
     {"A_MPEG/L3"        , AV_CODEC_ID_MP3},
     {"A_OPUS"           , AV_CODEC_ID_OPUS},
     {"A_OPUS/EXPERIMENTAL",AV_CODEC_ID_OPUS},