[MINOR] Remove unused import

### What changes were proposed in this pull request?

Remove unused import in `TimestampNTZType`.

### Why are the changes needed?

Cleanup

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

N/A

Closes #36448 from sunchao/remove.

Authored-by: Chao Sun <[email protected]>
Signed-off-by: Chao Sun <[email protected]>

Author: sunchao

sql/catalyst/src/main/scala/org/apache/spark/sql/types/TimestampNTZType.scala

@@ -17,7 +17,6 @@
 
 package org.apache.spark.sql.types
 
-import scala.math.Ordering
 import scala.reflect.runtime.universe.typeTag
 
 import org.apache.spark.annotation.Unstable