ffprobe: do not use deprecated AVStream.codec for max bitrate

Use the decoder context instead.

fftools/ffprobe.c

@@ -2754,10 +2754,10 @@ static int show_stream(WriterContext *w, AVFormatContext *fmt_ctx, int stream_id
     print_time("duration",    stream->duration, &stream->time_base);
     if (par->bit_rate > 0)     print_val    ("bit_rate", par->bit_rate, unit_bit_per_second_str);
     else                       print_str_opt("bit_rate", "N/A");
-#if FF_API_LAVF_AVCTX
-    if (stream->codec->rc_max_rate > 0) print_val ("max_bit_rate", stream->codec->rc_max_rate, unit_bit_per_second_str);
-    else                                print_str_opt("max_bit_rate", "N/A");
-#endif
+    if (dec_ctx && dec_ctx->rc_max_rate > 0)
+        print_val ("max_bit_rate", dec_ctx->rc_max_rate, unit_bit_per_second_str);
+    else
+        print_str_opt("max_bit_rate", "N/A");
     if (dec_ctx && dec_ctx->bits_per_raw_sample > 0) print_fmt("bits_per_raw_sample", "%d", dec_ctx->bits_per_raw_sample);
     else                                             print_str_opt("bits_per_raw_sample", "N/A");
     if (stream->nb_frames) print_fmt    ("nb_frames", "%"PRId64, stream->nb_frames);