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>

config: Fix up some configs to not use CPU aliases.

Support for CPU aliases were removed recently.

Change-Id: I3c1173dc34170d8639d95e52bf660f248848f77f
Reviewed-on: https://gem5-review.googlesource.com/3100
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

ruby: Detect garnet network-level deadlock.

This patch detects garnet network deadlock by monitoring
network interfaces. If a network interface continuously
fails to allocate virtual channels for a message, a
possible deadlock is detected.

ruby: Fix regressions and make Ruby configs Python packages

This patch moves the addition of network options into the Ruby module
to avoid the regressions all having to add it explicitly. Doing this
exposes an issue in our current config system though, namely the fact
that addtoPath is relative to the Python script being executed. Since
both example and regression scripts use the Ruby module we would end
up with two different (relative) paths being added. Instead we take a
first step at turning the config modules into Python packages, simply
by adding a __init__.py in the configs/ruby, configs/topologies and
configs/network subdirectories.

As a result, we can now add the top-level configs directory to the
Python search path, and then use the package names in the various
modules. The example scripts are also updated, and the messy
path-deducing variations in the scripts are unified.

ruby: garnet2.0
Revamped version of garnet with more optimized single-cycle routers,
more configurability, and cleaner code.

config: add a separate config file for the network.
This patch adds a new file configs/network/Network.py to setup the network,
instead of doing that within Ruby.py.