matroskadec: fix SRT subtitle duration

The codec id for SRT was changed and conditionals were not updated.

libavformat/matroskadec.c

@@ -2439,11 +2439,11 @@ static int matroska_parse_frame(MatroskaDemuxContext *matroska,
     else
         pkt->pts = timecode;
     pkt->pos = pos;
-    if (track->type != MATROSKA_TRACK_TYPE_SUBTITLE || st->codecpar->codec_id == AV_CODEC_ID_TEXT)
+    if (track->type != MATROSKA_TRACK_TYPE_SUBTITLE || st->codecpar->codec_id == AV_CODEC_ID_SRT)
         pkt->duration = duration;
 #if FF_API_CONVERGENCE_DURATION
 FF_DISABLE_DEPRECATION_WARNINGS
-    if (st->codecpar->codec_id == AV_CODEC_ID_TEXT)
+    if (st->codecpar->codec_id == AV_CODEC_ID_SRT)
         pkt->convergence_duration = duration;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif