drm/amdgpu/vcn: use vcn4 irqsrc header for VCN 4.0.3

Use vcn4 irqsrc header for VCN 4.0.3.

Signed-off-by: James Zhu <James.Zhu@amd.com>
Acked-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>