libavformat/utils.c: fixup create mythtv custom mpegts demuxer

Since MythTV now allows forcing the use of FFmpeg's demuxer,
these comparisons need an additional comparison against
"mpegts-ffmpeg" for the behavior of both to be the same.

This bug presented itself as incorrect durations of files
when using the mpegts-ffmpeg demuxer.

mythtv/external/FFmpeg/libavformat/utils.c

@@ -2957,7 +2957,8 @@ static void estimate_timings(AVFormatContext *ic, int64_t old_offset)
     }
 
     if ((!strcmp(ic->iformat->name, "mpeg") ||
-         !strcmp(ic->iformat->name, "mpegts")) &&
+         !strcmp(ic->iformat->name, "mpegts") ||
+         !strcmp(ic->iformat->name, "mpegts-ffmpeg")) &&
         file_size && (ic->pb->seekable & AVIO_SEEKABLE_NORMAL)) {
         /* get accurate estimate from the PTSes */
         estimate_timings_from_pts(ic, old_offset);
@@ -3670,7 +3671,7 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
         max_subtitle_analyze_duration = 30*AV_TIME_BASE;
         if (!strcmp(ic->iformat->name, "flv"))
             max_stream_analyze_duration = 90*AV_TIME_BASE;
-        if (!strcmp(ic->iformat->name, "mpeg") || !strcmp(ic->iformat->name, "mpegts"))
+        if (!strcmp(ic->iformat->name, "mpeg") || !strcmp(ic->iformat->name, "mpegts") || !strcmp(ic->iformat->name, "mpegts-ffmpeg"))
             max_stream_analyze_duration = 7*AV_TIME_BASE;
     }