Merge pull request #62304 from msau42/remove-err-check

Automatic merge from submit-queue (batch tested with PRs 61608, 62304). 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>.

Remove isNotDir error check

**What this PR does / why we need it**:
This check was supposed to handle the "subpath file" scenario, but:
1. It's wrong (should have been !)
2. It's not needed anymore. `IsLikelyNotMountPoint` was fixed to handle file mounts via https://github.com/kubernetes/kubernetes/pull/58433


**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
```

pkg/util/mount/mount.go

@@ -23,7 +23,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"syscall"
 )
 
 type FileType string
@@ -233,13 +232,6 @@ func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, e
 	return device, refCount, nil
 }
 
-func isNotDirErr(err error) bool {
-	if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOTDIR {
-		return true
-	}
-	return false
-}
-
 // IsNotMountPoint determines if a directory is a mountpoint.
 // It should return ErrNotExist when the directory does not exist.
 // This method uses the List() of all mountpoints
@@ -255,7 +247,7 @@ func IsNotMountPoint(mounter Interface, file string) (bool, error) {
 		notMnt = true
 		notMntErr = nil
 	}
-	if notMntErr != nil && isNotDirErr(notMntErr) {
+	if notMntErr != nil {
 		return notMnt, notMntErr
 	}
 	// identified as mountpoint, so return this fact