avcodec/avcodec: Remove AV_CODEC_FLAG2_DROP_FRAME_TIMECODE

It has been deprecated in 94d68a41fa
and can't be set via AVOptions. The only codecs that use it
(the MPEG-1/2 encoders) have private options for this.
So remove it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/avcodec.h

@@ -352,11 +352,6 @@ typedef struct RcOverride{
  */
 #define AV_CODEC_FLAG2_LOCAL_HEADER   (1 <<  3)
 
-/**
- * timecode is in drop frame format. DEPRECATED!!!!
- */
-#define AV_CODEC_FLAG2_DROP_FRAME_TIMECODE (1 << 13)
-
 /**
  * Input bitstream might be truncated at a packet boundaries
  * instead of only at frame boundaries.

libavcodec/mpeg12enc.c

@@ -249,7 +249,6 @@ static av_cold int encode_init(AVCodecContext *avctx)
         }
     }
 
-    mpeg12->drop_frame_timecode = mpeg12->drop_frame_timecode || !!(avctx->flags2 & AV_CODEC_FLAG2_DROP_FRAME_TIMECODE);
     if (mpeg12->drop_frame_timecode)
         mpeg12->tc.flags |= AV_TIMECODE_FLAG_DROPFRAME;
     if (mpeg12->drop_frame_timecode && mpeg12->frame_rate_index != 4) {