Fixes for TimingSimpleCPU under full system. Now boots Alpha Linux!

Fixes for TimingSimpleCPU under full system.  Now boots Alpha Linux!

src/cpu/simple/atomic.cc:
src/cpu/simple/base.cc:
    Move traceData->finalize() into postExecute().
src/cpu/simple/timing.cc:
    Fixes for full system.  Now boots Alpha Linux!
    - Handle ifetch faults, suspend/resume.
    - Delete memory request & packet objects on response.
    - Don't try to do split memory accesses on prefetch references
    (ISA description doesn't support this).
src/cpu/simple/timing.hh:
    Minor reorganization of internal methods.

--HG--
extra : convert_revision : 59e3ee5e4cb53c424ebdbe2e504d97e88c08a978