PR 1635/cpukit
* rtems/score/cpu.h, rtems/score/types.h: Refactoring of priority
handling, to isolate the bitmap implementation of priorities in the
supercore so that priority management is a little more modular. This
change is in anticipation of scheduler implementations that can
select how they manage tracking priority levels / finding the highest
priority ready task. Note that most of the changes here are simple
renaming, to clarify the use of the bitmap-based priority management.