[networking] SR-IOV: Correct PciPassthroughFilter description
[networking] SR-IOV: Correct PciPassthroughFilter description

Change-Id: I7baa227bb31a501da587452ba916d132fb6b5021
Closes-Bug: #1618820

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals