rbd: add configmap get clusterrole for provisioner

as provisioner need to get the configmap from
different namespace to check tenant configuration.
added the clusterrole get access for the same.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

deploy/rbd/kubernetes/csi-provisioner-rbac.yaml

@@ -52,6 +52,9 @@ rules:
   - apiGroups: ["snapshot.storage.k8s.io"]
     resources: ["volumesnapshotcontents/status"]
     verbs: ["update"]
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    verbs: ["get"]
 ---
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1