Add a human readable string for GPU device names rather than using the device ID in the code. This is intended to make code more readable. Change-Id: Id3ea74ca37422b1f4a0f09e5a9522d37b5998c1a Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70038 Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Matt Sinclair <mattdsinclair@gmail.com>