configs: Use absolute import paths

Use absoluate import paths to be Python 3 compatible. This also
imports absolute_import from __future__ to ensure that Python 2.7
behaves the same way as Python 3.

Change-Id: Ica06ed95814e9cd3e768b3e1785075e36f6e56d0
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/16708
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

configs, mem-ruby: fix issues with style in AMD license

fixes line length and white space issues.

Change-Id: Ia04a91ec68cae2bcdabeb93bb1a0f74e8e5486c3
Reviewed-on: https://gem5-review.googlesource.com/9801
Reviewed-by: Bradford Beckmann <brad.beckmann@amd.com>
Maintainer: Bradford Beckmann <brad.beckmann@amd.com>

gpu-compute: AMD's baseline GPU model