avformat: remove obsolete FF_API_NEW_STREAM cruft

Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/utils.c

@@ -3579,16 +3579,6 @@ void avformat_close_input(AVFormatContext **ps)
     avio_close(pb);
 }
 
-#if FF_API_NEW_STREAM
-AVStream *av_new_stream(AVFormatContext *s, int id)
-{
-    AVStream *st = avformat_new_stream(s, NULL);
-    if (st)
-        st->id = id;
-    return st;
-}
-#endif
-
 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
 {
     AVStream *st;