cpu,misc: Revert problematic terminology renames in BaseCPU

cpu,misc: Revert problematic terminology renames in BaseCPU

Due to gem5's use of duck-typing, we must termorarly revert the
terminology in BaseCPU back to master/slave to avoid issues.

This fixes https://gem5.atlassian.net/browse/GEM5-775.

Change-Id: Idf1cb99aa9568ee70943ebec96f27394d8167f8c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34495
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>