The powernv and pseries machines both provide hypervisor facilities
that are supported by KVM. This is a large and complicated set of
features that don't get much system-level testing in ppc tests.
Add a new test case for these which runs QEMU KVM inside the target.
This downloads an Alpine VM image, boots it and downloads and installs
the qemu package, then boots a virtual machine under it, re-using the
original Alpine VM image.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>