Add ppc64le architecture to kubetest2 available archs

[Rajalakshmi-Girish]

Addition of ppc64le arch worked fine when I ran make ci-binaries. The resulted file had below details when built on x86 machine:

[root@raji-x86-workspace1 ppc64le]# file kubetest2
kubetest2: ELF 64-bit LSB executable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), statically linked, with debug_info, not stripped
[root@raji-x86-workspace1 ppc64le]#

This change is needed for kubekins-e2e-v2 support on ppc64le. As at https://github.com/kubernetes/test-infra/blob/master/images/kubekins-e2e-v2/Dockerfile#L168 kubetest2 is referred.

kubekins issue :
kubernetes/test-infra#34345
Slack discussion: https://kubernetes.slack.com/archives/CCK68P2Q2/p1739538851706299?thread_ts=1739359083.466129&cid=CCK68P2Q2

[Rajalakshmi-Girish]

/sig k8s-infra

[mkumatag]

@Rajalakshmi-Girish can you link to the discussion and the kubekins issue you have created?

[mkumatag]

/lgtm

[Prajyot-Parab]

/lgtm

[Rajalakshmi-Girish]

/test pull-kubetest2-gce-legacy-up-down

[dims]

/assign @aojea @michelle192837 @upodroid

/lgtm

[aojea]

not much involved on the discussions but following the threads it seems there is a positive feedback on this so I'm going to approve to unblock the work

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aojea, mkumatag, Prajyot-Parab, Rajalakshmi-Girish

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