all platforms, main(): call clockqueue_init() just before sched_init_cpu()

all platforms, main(): call clockqueue_init() just before sched_init_cpu()

Move the clockqueue_init() call out of clockintr_cpu_init() and up
just before the sched_init_cpu() call for a given CPU.

This will allow sched_init_cpu() to allocate clockintr handles for a
given CPU's scheduler in a later patch.

Link: https://marc.info/?l=openbsd-tech&m=168661507607622&w=2
ok kettenis@, claudio@