drm/amdgpu: disable GFX CGCG in aldebaran

disable GFX CGCG and CGLS to workaround
a hardware issue found in aldebaran.

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>