drm/amdgpu: add VCN4 ip block support

Add VCN 4.0.5 initialization and decoder/encoder ring functions.

v2 - update license year (Leo Liu)

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>