ubuntu_kvm_smoke_test failed on G-5.8/H-5.11 P8 with qemu unexpectedly closed the monitor

Issue found on 5.8.0-52.59-generic with P8 node dryden

Test failed with:
  + SUT=bjf-test
  + SSH_KEY=/home/ubuntu/.ssh/id_rsa
  + SSH_OPTIONS='-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=quiet -i /home/ubuntu/.ssh/id_rsa'
  ++ lsb_release -c
  ++ awk '{print$2}'
  + DISTRO=groovy
  + ARCHITECTURE=ppc64el
  + trap cleanup EXIT
  + '[' -z ppc64el ']'
  + kvm-ok
  + '[' 0 '!=' 0 ']'
  + '[' '!' -f /home/ubuntu/.ssh/id_rsa ']'
  + ssh-keygen -f /home/ubuntu/.ssh/id_rsa -t rsa -N ''
  + '[' ppc64el = ppc64el ']'
  + sudo ppc64_cpu --smt=off
  ++ uvt-simplestreams-libvirt query
  ++ grep -P 'groovy.*ppc64el'
  ++ true
  + image=
  + '[' -z '' ']'
  + uvt-simplestreams-libvirt sync --source http://cloud-images.ubuntu.com/daily release=groovy arch=ppc64el
  + uvt-kvm create bjf-test release=groovy arch=ppc64el
  uvt-kvm: error: libvirt: internal error: qemu unexpectedly closed the monitor: 2021-06-03T02:08:53.646317Z qemu-system-ppc64le: Requested count cache flush assist capability level not supported by kvm, try appending -machine cap-ccf-assist=off