libavformat/mov: restore use of mfra time as dts

This was inadvertantly removed in 4a9d32baReviewed-by: Gyan Doshi <ffmpeg@gyani.pro>

libavformat/mov.c

@@ -4805,6 +4805,11 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
             pts = frag_stream_info->first_tfra_pts;
             av_log(c->fc, AV_LOG_DEBUG, "found mfra time %"PRId64
                     ", using it for pts\n", pts);
+        } else if (frag_stream_info->first_tfra_pts != AV_NOPTS_VALUE &&
+            c->use_mfra_for == FF_MOV_FLAG_MFRA_DTS) {
+            dts = frag_stream_info->first_tfra_pts;
+            av_log(c->fc, AV_LOG_DEBUG, "found mfra time %"PRId64
+                    ", using it for dts\n", pts);
         } else if (frag_stream_info->sidx_pts != AV_NOPTS_VALUE) {
             // FIXME: sidx earliest_presentation_time is *PTS*, s.b.
             // pts = frag_stream_info->sidx_pts;