OCPBUGS-14264: Updated the vSphere regions and zones tag info

Author: dfitzmau

modules/installation-configuration-parameters.adoc

@@ -1833,11 +1833,11 @@ a|Multiple IP addresses
 |String
 
 |`platform.vsphere.failureDomains.region`
-|You define a region by using a tag from the `openshift-region` tag category. The tag must be attached to the vCenter datacenter.
+|If you define multiple failure domains for your cluster, you must attach the tag to each vCenter datacenter. To define a region, use a tag from the `openshift-region` tag category. For a single vSphere datacenter environment, you do not need to attach a tag, but you must enter an alphanumeric value, such as `datacenter`, for the parameter.
 |String
 
 |`platform.vsphere.failureDomains.zone`
-|You define a zone by using a tag from the `openshift-zone` tag category. The tag must be attached to the vCenter datacenter.
+|If you define multiple failure domains for your cluster, you must attach the tag to each vCenter cluster. To define a zone, use a tag from the `openshift-zone` tag category. For a single vSphere datacenter environment, you do not need to attach a tag, but you must enter an alphanumeric value, such as `cluster`, for the parameter.
 |`String`
 
 |`platform.vsphere.ingressVIPs`