avformat/mux: Don't access AVStream's internal AVCodecContext

An AVStream's internal AVCodecContext is pretty much unused for muxing:
The only place where any of its fields are set is
avformat_transfer_internal_stream_timing_info() where its time base is
set based upon the desired output format. The max_b_frames field is
never set at all, so don't read it in mux.c.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/mux.c

@@ -509,7 +509,7 @@ FF_DISABLE_DEPRECATION_WARNINGS
 //FIXME merge with compute_pkt_fields
 static int compute_muxer_pkt_fields(AVFormatContext *s, AVStream *st, AVPacket *pkt)
 {
-    int delay = FFMAX(st->codecpar->video_delay, st->internal->avctx->max_b_frames > 0);
+    int delay = st->codecpar->video_delay;
     int i;
     int frame_size;