PROBLEM:  (76155, 76156, 77967) (PATCH ID: OSF445-039)
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This patch fixes a kernel memory fault caused by either one
of the following conditions:

1.  On EV6 platforms, when the debugger is used to view
      the OT_DEVMAP object mapping memory in I/O space
      that is mapped to a user process.

2.  When  routine pmap_coproc_exit_notify() modifies
     the pmaps' coproc_tbi function to be 0, a null
     pointer, while it is being checked by routine
     pmap_remove_all()