fix cpu builder to build the correct name...

fix cpu builder to build the correct name...

add activateThread event and functions

src/cpu/o3/alpha/cpu_builder.cc:
    Have CPU builder build a DerivO3CPU not a DerivAlphaO3CPU
src/cpu/o3/cpu.cc:
    add activateThread Event

    add activateThread function

    adjust activateContext to schedule a thread to activate within the
    CPU instead of activating thread right away. This will lead to stages
    trying to use threads that  arent ready yet and wasting execution time & possibly
    performance.
src/cpu/o3/cpu.hh:
    add activateThread Event

    add activateThread function

    add schedule/descheculed activate thread event

--HG--
extra : convert_revision : 236d30dc160910507ad36f7f527ab185ed38dc04