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>.

Fixing comments in types.go to describe the changes for CSI driver default FS type override fix

This PR fixes the comment in types.go which was made in the commit https://github.com/kubernetes/kubernetes/pull/65499/commits/5dfe7b5758141b24fa5899618003eb3f2a9289b4 
In the above commit,  the change that fixed the override of default FSType for CSI driver was made. However the comments in types.go were made for   GCEPersistentDiskVolumeSource and RBDVolumeSource respectively. This commit fixes that comment to reflect the changes for CSI driver

```release-note
none
```