drm/amdgpu: update gfx golden setting for dimgrey_cavefish

Set LDS_CONFIG to 0x20 on dimgrey_cavefish to fix GPU hang.

Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Jiansong Chen <Jiansong.Chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>