drm/amdgpu/discovery: add GMC 11.0 Support

Enable GMC 11.0 on asics where it is present.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>