Simplify default export

This removes unnecessary variable declarations where the default object is an object.

src/ol/geom/GeometryLayout.js

@@ -1,17 +1,16 @@
 /**
  * @module ol/geom/GeometryLayout
  */
+
 /**
  * The coordinate layout for geometries, indicating whether a 3rd or 4th z ('Z')
  * or measure ('M') coordinate is available. Supported values are `'XY'`,
  * `'XYZ'`, `'XYM'`, `'XYZM'`.
  * @enum {string}
  */
-var GeometryLayout = {
+export default {
   XY: 'XY',
   XYZ: 'XYZ',
   XYM: 'XYM',
   XYZM: 'XYZM'
 };
-
-export default GeometryLayout;