ffmpeg_opts: remove lowres check

The st->codec values are updated based on the lowres factor by
avformat_find_stream_info() when it runs an instance of the decoder internally,
and the same thing happens in ffmpeg.c when we open ist->dec_ctx with
avcodec_open2(), so these assignments are redundant.

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

fftools/ffmpeg_opt.c

@@ -867,15 +867,6 @@ static void add_input_streams(OptionsContext *o, AVFormatContext *ic)
         case AVMEDIA_TYPE_VIDEO:
             if(!ist->dec)
                 ist->dec = avcodec_find_decoder(par->codec_id);
-#if FF_API_LOWRES
-            if (st->codec->lowres) {
-                ist->dec_ctx->lowres = st->codec->lowres;
-                ist->dec_ctx->width  = st->codec->width;
-                ist->dec_ctx->height = st->codec->height;
-                ist->dec_ctx->coded_width  = st->codec->coded_width;
-                ist->dec_ctx->coded_height = st->codec->coded_height;
-            }
-#endif
 
             // avformat_find_stream_info() doesn't set this for us anymore.
             ist->dec_ctx->framerate = st->avg_frame_rate;