reduce useless check in resctrl file system

[Rouzip]

Fix #3263

In the resctrl file system, there will be automatically created mode and size files, so we can remove the useless check for them in the findGroup function.

[k8s-ci-robot]

Hi @Rouzip. Thanks for your PR.

I'm waiting for a google 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[Rouzip]

Hello, can you help review my pr? @Creatone

[Creatone]

/ok-to-test

[Creatone]

LGTM