AtomicSimpleCPU: Refactor resume() code to have a cleaner control path.
AtomicSimpleCPU: Refactor resume() code to have a cleaner control path.

andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin