kernel: fix missing SMP_MAX_CPUS on non-x86

* Regression introduced due to scheduler change
* Drop MAX_BOOT_CPUS as it is no longer used
kernel: fix missing cpu cache defines non-x86

* Regression introduced due to scheduler change
* Other other non-x86, non-ppc, and non-arm platforms
  need evalulated for this metric
kernel: Add missing PPC CPU functions for idle / pause