remove rbac instruction (#8442)

content/en/docs/setup/platform-setup/gke/index.md

@@ -69,13 +69,3 @@ Follow these instructions to prepare a GKE cluster for Istio.
         --zone $ZONE \
         --project $PROJECT_ID
     {{< /text >}}
-
-1. Grant cluster administrator (admin) permissions to the current user. To
-   create the necessary RBAC rules for Istio, the current user requires admin
-   permissions.
-
-    {{< text bash >}}
-    $ kubectl create clusterrolebinding cluster-admin-binding \
-        --clusterrole=cluster-admin \
-        --user=$(gcloud config get-value core/account)
-    {{< /text >}}