mem-ruby: Standardize Bloom Filter deletion support

mem-ruby: Standardize Bloom Filter deletion support

Standard Bloom Filters do not support element deletion by default,
however some variants do. Allow calling the unset function with
all filters, and do nothing by default.

Change-Id: Icf4b0f8b997c4c70fa714b2576474810275db78b
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18730
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>