Fix up default enconfig name

[jayanthvn]

What type of PR is this?
bug

Which issue does this PR fix:
Fixes #1917

What does this PR do / Why do we need it:
Default eniconfig name recommended in EKS docs - https://aws.amazon.com/premiumsupport/knowledge-center/eks-multiple-cidr-ranges/ is AZ name but we used to build the name as region + key(az name) but not annotating the node. Instead we just default it to AZ name and the below label setting will automatically pick the nodes AZ -

kubectl set env daemonset aws-node \
    -n kube-system ENI_CONFIG_LABEL_DEF=topology.kubernetes.io/zone

If an issue # is not available please add repro steps and logs from IPAMD/CNI showing the issue:

Testing done on this change:

Yes

---
# Source: aws-vpc-cni/templates/eniconfig.yaml
apiVersion: crd.k8s.amazonaws.com/v1alpha1
kind: ENIConfig
metadata:
  name: us-west-2a
spec:
  securityGroups:
    - sg-123
  subnet: subnet-123
---
# Source: aws-vpc-cni/templates/eniconfig.yaml
apiVersion: crd.k8s.amazonaws.com/v1alpha1
kind: ENIConfig
metadata:
  name: us-west-2b
spec:
  securityGroups:
    - sg-456
  subnet: subnet-456
---

Automation added to e2e:

N/A

Will this PR introduce any new dependencies?:

N/A

Will this break upgrades or downgrades. Has updating a running cluster been tested?:
N/A

Does this change require updates to the CNI daemonset config files to work?:

N/A

Does this PR introduce any user-facing change?:

N/A

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[haouc]

lgtm

[technotaff-nbs]

This change has broken our deployment, I think the intention was that you set your naming inside your values file to "a", "b", or "c". We have changed our values-file generator now but this was a breaking-change.

[joshuastern]

This change has broken our deployment, I think the intention was that you set your naming inside your values file to "a", "b", or "c". We have changed our values-file generator now but this was a breaking-change.

We experienced the same issue.

[jayanthvn]

Sorry for the inconvenience. This was done to keep the helm chart same as the docs recommendation.