Use O3DynInst in cpu_models.py and in static_inst_exec_sigs.hh instead of a specific...

Use O3DynInst in cpu_models.py and in static_inst_exec_sigs.hh instead of a specific ISA dyn. inst.

src/cpu/cpu_models.py:
    Use O3DynInst
src/cpu/o3/dyn_inst.hh:
    declare O3DynInst here based off of ISA ... this must be updated for each ISA.
src/cpu/static_inst.hh:
    take out O3 forward declarations here and include header file to keep this file clean

--HG--
extra : convert_revision : 0d65463479c3cfc2d1154935b1032dae32c5efd0