drm/amdgpu: add ip offset header for navi12 (v2)

This adds the absolute offsets of each IP regiser block.

v2: Squash in MP1 update

Signed-off-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>