Description of problem:
Volume is not provisioned when storageclass Region is provided but without zone info
https://github.com/openshift/ibm-vpc-block-csi-driver/pull/12#discussion_r852070029

Version-Release number of selected component (if applicable):
https://github.com/openshift/ibm-vpc-block-csi-driver/pull/12

How reproducible:
Always

Steps to Reproduce:
1.Install OCP on IBM cluster
2.Create sc without zone info.
allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
    app: ibm-vpc-block-csi-driver
    razee/force-apply: "true"
  name: sc-region
parameters:
  csi.storage.k8s.io/fstype: ext4
  encrypted: "false"
  encryptionKey: ""
  profile: 10iops-tier
  region: "eu-gb"
  resourceGroup: ""
  tags: ""
  zone: ""
provisioner: vpc.block.csi.ibm.io
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer
3.Create pvc/pod

  Warning  ProvisioningFailed    10s                vpc.block.csi.ibm.io_ibm-vpc-block-csi-controller-5c44694f6b-d7ql4_a4a046c6-17ab-4c09-a429-80c2f68f541a  failed to provision volume with StorageClass "sc-region": rpc error: code = InvalidArgument desc = {RequestID: b62ad161-0dfc-43c5-a6fb-fc4b05b93241 , Code: InvalidParameters, Description: Failed to extract parameters, BackendError: zone parameter is empty in storage class for region eu-gb, Action: Please provide valid parameters}

no region provided in sc/no region and zone in sc
PV could provision successfully

Actual results:
Volume is not provisioned.

Expected results:

Master Log:

Node Log (of failed PODs):

PV Dump:

PVC Dump:

StorageClass Dump (if StorageClass used by PV/PVC):

Additional info: