Minor fixes to the Ruby stride prefetcher. This includes removing unused statistics and changing where/when some statistics are updated. Change-Id: If758bf009f53fad277cb3cd754d57a0b10737599 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24363 Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br> Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu> Tested-by: kokoro <noreply+kokoro@google.com>