drm/amdgpu: correct xgmi ras error count reset

The error count reset for xgmi3x16 pcs is missed.

Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>