tests: Fix path for module imports in ARM system configs

Change-Id: I6fd660da3899de1f8c61bf012532ff0437467302
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4220
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
5 files changed