six is used in develop, but wasn't used in the GCN staging branch. Change-Id: Ic1ca42df871d1e683c288282497267d00421609f Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32235 Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>