drm/amdgpu: add the files of HDP v5.2 block

This patch is to add the files of HDP v5.2 block.
HDP (Host Data Port) is the IP which handles
host access to VRAM via the PCI BAR.

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