修复mapboxgl mapvlayer 参数个数判断

Author: xilanhuaweidapao

src/mapboxgl/overlay/MapvLayer.js

@@ -21,7 +21,7 @@ import {
  */
 export class MapvLayer {
  constructor(map, dataSet, mapVOptions) {
- if (map instanceof mapboxgl.Map) {
+ if (arguments.length === 3) {
  this.map = map;
  delete mapVOptions['layerID'];
  this.mapVOptions = mapVOptions;