Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
kubeadm: Fix a small config upgrading issue with .CloudProvider
**What this PR does / why we need it**:
Fixes a panic in the conversion code where `.NodeRegistration.KubeletExtraArgs` could be nil :/
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
@kubernetes/sig-cluster-lifecycle-pr-reviews
/kind bug
/priority critical-urgent
/milestone v1.11
/status approved-for-milestone
b005f2fba3