Remove lowres support from cdgraphics decoder

The lowres support doesn't work correctly (crops the video), so let's remove it.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/cdgraphics.c

@@ -377,6 +377,5 @@ AVCodec ff_cdgraphics_decoder = {
     cdg_decode_end,
     cdg_decode_frame,
     CODEC_CAP_DR1,
-    .max_lowres = 5,
     .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
 };