add puf_mode (bool logic) for gem5

change the following files:

gem5/configs/common/CacheConfig.py

gem5/configs/common/Caches.py

          

  gem5/configs/common/Options.py

 

gem5/src/mem/cache/Cache.py

 

 gem5/src/mem/cache/base.hh

 

 gem5/src/mem/cache/base.cc