We should block non-wakeup interrupts until we're in the resume path and

We should block non-wakeup interrupts until we're in the resume path and
have disabled interrupts at the CPU level again.  So instead of
cpu_suspended use a new intr_suspended variable that is set and cleared in
intr_enable_wakeup() and intr_disable_wakeup().

ok mglocker@, mlarkin@