Add a note for NIC drivers
Add a note for NIC drivers

Sriov enabling may or may not work depending on device
drivers used, adding a note for alert to make sure drivers
are updated while using sriov-capability.

Change-Id: Idbe3df3c77a419ed86fcf7a3a3b614aecad70c67
Closes-Bug: #1614564

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