x4x boards: Factor out MAX_CPUS
LGA775 CPUs can have at most 4 threads, and Eaglelake supports them.
As this socket is also used by other chipsets, temporarily place this
symbol into the northbridge scope until all chipsets are factored out.
Change-Id: I6e01363d995e135815cc70779e0cd5baf806cf60
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41841
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>