Removed several "#if BX_CPU_LEVEL < 2" clauses, since stack64.cc   is only compiled for x86-64.
Removed several "#if BX_CPU_LEVEL < 2" clauses, since stack64.cc
  is only compiled for x86-64.

marmolejo/bochs-zet,marmolejo/bochs-zet,marmolejo/bochs-zet,marmolejo/bochs-zet,marmolejo/bochs-zet