This is a new feature available at 4.7.11.

From OCP docs:
An existing Route 53 private hosted zone for the cluster. You can only use a pre-existing hosted zone when also supplying your own VPC. The hosted zone must already be associated with the user-provided VPC before installation. Also, the domain of the hosted zone must be the cluster domain or a parent of the cluster domain.

cc gdoyle-1 smordech@redhat.com wgordon17

Updated mockups for OSD wizard networking changes:  https://marvelapp.com/prototype/761f93c/screen/81487561