title: default value for multiple select in form antd 4
body: <p>I'm unable to set default value for multi select inside form.</p>
  
  <p><strong>Use Case:</strong>
  I have created a react component that renders a select with some default props that I need in every form.
  Now I want to set default value for that select from the <code>defaultValue</code> prop of select instead of passing <code>initialValues</code> to every form.</p>
  
  <p>My react component looks like:</p>
  
  <pre><code>import React, { Component } from 'react';
  import { Form, Select } from 'antd';
  
  class FormSelect extends Component {
    render() {
      const {name, label, rules, onSelect, disabled, options, mode} = this.props;
  
      let defaultValue;
      if (mode === 'tags' || mode === 'multiple'){
        defaultValue = [];
      }
  
      return (
        &lt;Form.Item
          hasFeedback
          name={name}
          label={label}
          rules={rules}
        &gt;
          &lt;Select
            showSearch
            mode={mode}
            tokenSeparators={[',']}
            defaultValue={defaultValue}
            onSelect={onSelect}
            disabled={disabled}
          &gt;
            {
              options.map((op) =&gt; (
                &lt;Select.Option key={op.value} value={op.value} label={op.label}&gt;
                  {op.label}
                &lt;/Select.Option&gt;
              ))
            }
          &lt;/Select&gt;
        &lt;/Form.Item&gt;
      );
    }
  }
  export default FormSelect;
  </code></pre>
  
  <p>The problem is when I set the <code>defaultValue</code> prop of select the value is shown in UI but when the form is submitted the defaultValue is ignored and value of select field remains <code>undefined</code></p>