Update README.md to reference OPENSHIFT.md instead of external repo

Agent-Logs-Url: https://github.com/intel/intel-device-plugins-for-kubernetes/sessions/639aa4ea-6bf8-4df2-bace-6158372ef9a4

Co-authored-by: mythi <1049565+mythi@users.noreply.github.com>

Author: Copilot

README.md

@@ -200,7 +200,7 @@ to those custom resources.
 
 The [Device plugins operator README](cmd/operator/README.md) gives the installation and usage details for the community operator available on [operatorhub.io](https://operatorhub.io/operator/intel-device-plugins-operator).
 
-The [Device plugins Operator for OpenShift](https://github.com/intel/intel-technology-enabling-for-openshift) gives the installation and usage details for the operator available on [Red Hat OpenShift Container Platform](https://catalog.redhat.com/software/operators/detail/61e9f2d7b9cdd99018fc5736).
+The [Device plugins Operator for OpenShift](OPENSHIFT.md) gives the installation and usage details for the operator available on [Red Hat OpenShift Container Platform](https://catalog.redhat.com/software/operators/detail/61e9f2d7b9cdd99018fc5736).
 
 ## Intel GPU Level-Zero sidecar