Pull enabling/disabling wakeup interrupt handling out of the aplintc(4)

Pull enabling/disabling wakeup interrupt handling out of the aplintc(4)
DVACT_SUSPEND/DVACT_RESUME handling and push it into the MD code that
handles "suspend-to-idle".  This way a failure in DVACT_SUSPEND handling
will not result in hosed interrupts on the primary interrupt controller
if we abort the suspend operation.

requested by deraadt@
ok patrick@