tidb-operator volume-snapshot restore failure when tikv request cpu less or equal to 1

[fengou1]

Bug Report

operator tikv configuration

    requests:
      cpu: 1
      memory: 4Gi
      storage: 20Gi

following https://docs.pingcap.com/zh/tidb-in-kubernetes/stable/restore-from-aws-s3-by-snapshot to do the volume snapshot restore.

What version of TiKV are you using?

v6.5.0

What operating system and CPU are you using?

centos

Steps to reproduce

1. perform volume-snapshot backup following https://docs.pingcap.com/zh/tidb-in-kubernetes/stable/backup-to-aws-s3-by-snapshot
2. perform volume-snapshot restore following https://docs.pingcap.com/zh/tidb-in-kubernetes/stable/restore-from-aws-s3-by-snapshot to do the volume snapshot restore.

What did you expect?

restore shall be success

What did happened?

restore failure with the following error
[2023/01/04 10:00:19.751 +00:00] [FATAL] [[setup.rs:309](http://setup.rs:309/)] ["invalid configuration: max_background_jobs should be greater than 0 and less than or equal to 20"]