Add missing LISTENING port states to the list of states reported in metrics

[edcdavid]

This is to add support for the LISTENING port state in metrics. Using a new integer value 5 for backward compatibility (so as to not change previous mappings).
The LISTENING state is reached when multiple follower ports are receiving PTP frames but only one is selected to become a SLAVE, in slave only mode. The other ports state should be LISTENING (whether they receive PTP frames are received or not).

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: edcdavid
Once this PR has been reviewed and has the lgtm label, please assign schseba for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[edcdavid]

/retest

[aneeshkp]

you might have to do the same to cloud-event-proxy

[openshift-ci]

@edcdavid: all tests passed!

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.