Revert "avformat/movenchint: Fix movhinting with ff_rtp_chain_mux_open() from abb810db036628e11a5171134ebe320b187ee6d6"

This has become unneeded due to f797b134ca

This reverts commit 1fe40e1b05.

libavformat/movenchint.c

@@ -33,7 +33,6 @@ int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index)
     MOVTrack *src_track = &mov->tracks[src_index];
     AVStream *src_st    = s->streams[src_index];
     int ret = AVERROR(ENOMEM);
-    AVRational src_timebase = src_st->time_base;
 
     track->tag = MKTAG('r','t','p',' ');
     track->src_track = src_index;
@@ -49,8 +48,6 @@ int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index)
     if (ret < 0)
         goto fail;
 
-    src_st->time_base = src_timebase; // prevent ff_rtp_chain_mux_open() from corrupting the timebase
-
     /* Copy the RTP AVStream timebase back to the hint AVStream */
     track->timescale = track->rtp_ctx->streams[0]->time_base.den;