Remove use of CtlplaneNetmask

[bshephar]

This change removes use of CtlplaneNetmask in line with the changes proposed in:
openstack-k8s-operators/openstack-baremetal-operator#241

Jira: https://issues.redhat.com/browse/OSPRH-12686

[openshift-ci]

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[openshift-ci]

@bshephar: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/functional	f39669a	link	true	/test functional
ci/prow/openstack-operator-build-deploy-kuttl	f39669a	link	true	/test openstack-operator-build-deploy-kuttl

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