Short circuit if we're running on the CPU that we want to sync with.  Fixes suspend on machines with em(4) now that it uses intr_barrier(9).
Short circuit if we're running on the CPU that we want to sync with.  Fixes
suspend on machines with em(4) now that it uses intr_barrier(9).

ok krw@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars