Modified instruction decode method.

Modified instruction decode method.
Make code compatible with new decode method.

src/arch/alpha/remote_gdb.cc:
src/cpu/base_dyn_inst_impl.hh:
src/cpu/exetrace.cc:
src/cpu/simple/base.cc:
    Make code compatible with new decode method.
src/cpu/static_inst.cc:
src/cpu/static_inst.hh:
    Modified instruction decode method.

--HG--
extra : convert_revision : a9a6d3a16fff59bc95d0606ea344bd57e71b8d0a