website: Add a note on CPU/ISA independence

Change-Id: Ie44f8f437895cddddecaf9b0c5baf74eb657ae1b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/62072
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby Bruce <bbruce@ucdavis.edu>
2 files changed