util: Use dist_bigLITTLE as an example dist-gem5 node

This is one of the steps towards deprecating fs.py usage

With the patch we are updating the commandline and default
kernel + disk image to reflect a more modern version [1]

[1]: https://www.gem5.org/documentation/general_docs/\
    fullsystem/guest_binaries

Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Change-Id: I82fd5d232b6fd9a1962d0896a1d9462caad7ebed
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62513
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
1 file changed