CPX-SP has a CSTACK and 3 PSTACKs. Clean up the HOB header file to remove reference to non-existing PSTACKs. Adjust mainboard code accordingly. Signed-off-by: Jonathan Zhang <jonzhang@fb.com> Change-Id: Ic52b01cd89fb5b3fce64686d91f017f405566acd Reviewed-on: https://review.coreboot.org/c/coreboot/+/44279 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Maxim Polyakov <max.senia.poliak@gmail.com> Reviewed-by: Angel Pons <th3fanbus@gmail.com>