stdlib: Adding clock_domain to GUPSGenerators

This change adds clock domain as a parameter to the GUPSGen
classes. This way the generator and other components can
work on different clock frequencies.

Change-Id: If916877a57b3c3a61073dad075e35f3f93af8459
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53163
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
4 files changed