drm/amdgpu: Use the right struct for VCN v5.0.1

VCN IP versions >= 5.0 uses VCN5 fw shared struct.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>