mem: Add HBM2 pseudo channel interface configuration

Change-Id: I5826e50a35ee9dda054a164cfda616ca0ffe82e5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59734
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Wendy Elsasser <welsasser@rambus.com>
2 files changed