6345 remove xhat support

*** 62,72 ****
  CORE_OBJS +=    memscrub.o
  CORE_OBJS +=    memscrub_asm.o
  CORE_OBJS +=    ppage.o
  CORE_OBJS +=    sfmmu_kdi.o
  CORE_OBJS +=    swtch.o
- CORE_OBJS +=    xhat_sfmmu.o
  
  #
  #       Some objects must be linked at the front of the image (or
  #       near other objects at the front of the image).
  #
--- 62,71 ----