Description of problem:
There is no PCI passthrough configuration on computes after the upgrade. Found passthrough_whitelist not set /var/lib/config-data/puppet-generated/nova_libvirt/etc/nova/nova.conf:
~~~
#
# White list of PCI devices available to VMs. For more information, refer to the
# documentation. (multi valued)
# Deprecated group;name - DEFAULT;pci_passthrough_whitelist
#passthrough_whitelist =
~~~

The sriov-config.yaml provided:
~~~
[stack@undercloud-0 ~]$ cat ospd-16.2-vxlan-hw-offload-ctlplane-dataplane-bonding-hybrid/sriov-config.yaml 
---
parameter_defaults:
  ComputeSriovOffloadParameters:
    NovaPCIPassthrough:
      # Geneve/VxLAN configuration for Mellanox HW-Offload NIC
      - devname: "enp4s0f0"
        trusted: "true"
        physical_network: null
      # VLAN configuration for Mellanox HW-Offload NIC
      - devname: "enp4s0f1"
        trusted: "true"
        physical_network: mx-network

[stack@undercloud-0 ~]$ grep sriov-config.yaml overcloud_deploy.sh
-e /home/stack/ospd-16.2-vxlan-hw-offload-ctlplane-dataplane-bonding-hybrid/sriov-config.yaml \
~~~

According to sriov-config.yaml we should have the nova.conf file like this:
~~~
#
# White list of PCI devices available to VMs. For more information, refer to the
# documentation. (multi valued)
# Deprecated group;name - DEFAULT;pci_passthrough_whitelist
#passthrough_whitelist =
passthrough_whitelist={"devname":"enp4s0f0","physical_network":null,"trusted":"true"}
passthrough_whitelist={"devname":"enp4s0f1","physical_network":"mx-network","trusted":"true"}
~~~

Version-Release number of selected component (if applicable):
17.1 FFU

How reproducible:
100%

Steps to Reproduce:
1.Perform FFU
2.
3.

Actual results:

Expected results:

Additional info: