Remove ETCD_UNSUPPORTED_ARCH since etcdmain officially supports "arm64"

[yankay]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Remove ETCD_UNSUPPORTED_ARCH since etcdmain officially supports "arm64"..

The etcd env ETCD_UNSUPPORTED_ARCH, and etcd args etcd-unsupported-arch in arm64 is no need anymore in etcd 3.5.x
( https://github.com/etcd-io/etcd/blob/v3.5.0/server/etcdmain/etcd.go#L468 )

Which issue(s) this PR fixes:

When 'etcd_deployment_type: kubeadm' the in arm64, it fails:

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

remove the 'etcd-unsupported-arch' args to fix the etcd issue  in arm64

[k8s-ci-robot]

Hi @yankay. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[liupeng0518]

/lgtm

[yankay]

HI @cristicalin @floryut , would you please review the PR.

[floryut]

@yankay Nice, thanks 👍

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: floryut, yankay

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[yankay]

Thank you @liupeng0518 @floryut for the PR review.