drm/amdgpu: add vcn 4_0_5 header files

Add VCN 4.0.5 registers

v2 - Add license header (Alexander Deucher)
v3 - updates (Alex)

Signed-off-by: Saleemkhan Jamadar <saleemkhan.jamadar@amd.com>
Acked-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>