<select name="role_id" id="" class="form-control" required>

    {volist name="roleData" key="key" id="vo"}

        <option value="{$vo.id}" {php}if(isset($data['role_id'])){   {/php} {$data['role_id']==$vo['id'] ? 'selected' : ''}{php}}{/php}>{$vo['name']}</option>

    {/volist}

<select name="role_id" id="" class="form-control" required>

    {volist name="roleData" key="key" id="vo"}

        {eq name="vo['id']" value="$data.role_id"}

        <option value="{$vo['id']}" selected>{$vo['name']}</option>

        {else/}

        <option value="{$vo['id']}">{$vo['name']}</option>

        {/eq}

    {/volist}

</select>