avformat/mpegts: Do not ignore registration descriptors when probing is enabled

This is required for the (not yet in git) private stream detection/export,
no other testcase known
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mpegts.c

@@ -1758,7 +1758,7 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
     case 0x05: /* registration descriptor */
         st->codec->codec_tag = bytestream_get_le32(pp);
         av_log(fc, AV_LOG_TRACE, "reg_desc=%.4s\n", (char *)&st->codec->codec_tag);
-        if (st->codec->codec_id == AV_CODEC_ID_NONE)
+        if (st->codec->codec_id == AV_CODEC_ID_NONE || st->request_probe > 0)
             mpegts_find_stream_type(st, st->codec->codec_tag, REGD_types);
         break;
     case 0x52: /* stream identifier descriptor */