drm/amdgpu: add asd fw check before loading asd

asd is not ready for some ASICs in early stage, and psp->asd_fw is more generic than ASIC name in the check.

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