avcodec/h263dec, mpeg12dec: Remove redundant writes

ff_mpv_decode_init() already sets MpegEncContext.codec_id.

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

libavcodec/h263dec.c

@@ -130,7 +130,6 @@ av_cold int ff_h263_decode_init(AVCodecContext *avctx)
                avctx->codec->id);
         return AVERROR(ENOSYS);
     }
-    s->codec_id    = avctx->codec->id;
 
     if (avctx->codec_tag == AV_RL32("L263") || avctx->codec_tag == AV_RL32("S263"))
         if (avctx->extradata_size == 56 && avctx->extradata[0] == 1)

libavcodec/mpeg12dec.c

@@ -1067,7 +1067,6 @@ static av_cold int mpeg_decode_init(AVCodecContext *avctx)
     s->mpeg_enc_ctx_allocated      = 0;
     s->mpeg_enc_ctx.picture_number = 0;
     s->repeat_field                = 0;
-    s->mpeg_enc_ctx.codec_id       = avctx->codec->id;
     avctx->color_range             = AVCOL_RANGE_MPEG;
     return 0;
 }