Different GPUFS disk images have different root partitions that Linux
needs to boot from. In particular, Ubuntu's new installer has a GRUB
partition that cannot seem to be removed. Adding this as an option
prevents needing to edit a config script to change one character each
time a different disk image is used.
Change-Id: Iac2996ea096047281891a70aa2901401ac9746fc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/71918
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>