Bug 541294 covers migrating from smolt to lshw for inventory scanning. One outcome of that is that the inventory task should work on ppc64le systems. This issue currently isn't expected to require additional work on the inventory task - it is included to ensure ppc64le support is specifically tested, allowing the original bug to just cover existing architectures.
There may be other changes necessary, but this is the first: http://gerrit.beaker-project.org/#/c/4118/
This patch was sufficient to get beaker-system-scan running on ppc64le.