Revert "clockintr_cpu_init: initialize starting offsets with clockintr_stagger()"

Revert "clockintr_cpu_init: initialize starting offsets with clockintr_stagger()"

octeon machines do not increment the global variable "ncpus"
(init_main.c) in the same spot as other platforms, which violates the
KASSERT in clockintr_stagger(), causing a panic.

We need to bring octeon's behavior into alignment with every other
platform before proceeding with this patch.

Reported and debugged by bluhm@.