drm/amdgpu: add rsmu v_0_0_2 ip headers

remote smu (rsmu) is a sub-block used as ip register interface,
error handling, reset generation.etc

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Dennis Li <dennis.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>