Remove olx.source.WMTSOptions#maxZoom option

The option is not handled by `ol.source.WMTS`

externs/olx.js

@@ -5903,7 +5903,6 @@ olx.source.VectorOptions.prototype.wrapX;
  *     matrixSet: string,
  *     dimensions: (!Object|undefined),
  *     url: (string|undefined),
- *     maxZoom: (number|undefined),
  *     tileLoadFunction: (ol.TileLoadFunctionType|undefined),
  *     urls: (Array.<string>|undefined),
  *     tileClass: (function(new: ol.ImageTile, ol.TileCoord,
@@ -6064,14 +6063,6 @@ olx.source.WMTSOptions.prototype.dimensions;
 olx.source.WMTSOptions.prototype.url;
 
 
-/**
- * Maximum zoom.
- * @type {number|undefined}
- * @api
- */
-olx.source.WMTSOptions.prototype.maxZoom;
-
-
 /**
  * Optional function to load a tile given a URL. The default is
  * ```js