GPU_VIPER.py uses FileSystemConfig to register CPUs and caches in SE mode. Without the import, it crashes. Change-Id: I539a4060d705f6e1b9a12aca7836eca271f61557 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32675 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>