[EKS] [aws-efs-csi-driver]: support for affinity configuration in EKS add-on

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**Tell us about your request**
I would like to configure affinity (node affinity) on `aws-efs-csi-driver` EKS add-on configuration. Currently we are managing add-on definition via Terraform.

**Which service(s) is this request for?**
EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
Affinity configuration is not exposed as an add-on configuration item

**Are you currently working around this issue?**
No

**Additional context**
Affinity configuration is already supported in the official Helm chart and in `aws-ebs-csi-driver` add-on

Start by comparing the official aws-efs-csi-driver Helm chart with the aws-ebs-csi-driver EKS add-on, since the issue says affinity is supported there. Determine how node affinity should be exposed in the EKS add-on configuration and verify that the resulting add-on definition can configure it.

Written by the indexing model from the issue text.