Since its introduction in v1.0.5-rc1-19-g6e13860cb4 the
qemuTeardownHostdevCgroup() does nothing unless the passed
hostdev is a PCI device with VFIO backend. This seems
unnecessary.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Cole Robinson <crobinso@redhat.com>