drm/amdgpu: Query and report boot status

Query boot status and report boot errors. A follow
up change is needed to stop GPU initialization if boot
fails.

v2: only invoke the call for dGPU (Le/Lijo)

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Reviewed-by: Le Ma <le.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>