drm/amdgpu: add navi10 common ip block (v3)

This adds the core SOC code for navi asics.

v1: add place holder and initial basic function (Ray)
v2: add new introduced functions to avoid reference
    NULL pointer (Hawking)
v3L squash in updates (Alex)

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>