The method serviceEntityInfo has only 2 possible arguments, content id and display name:

public function serviceEntityInfo ($iContentId = 0, $sDisplay = false)

So call of it will have the following view (example with Persons Info block):

$sCode = BxDolService::call('bx_persons', 'entity_info', array($iContentId, 'bx_person_view'));

So the bold line means the array of the given arguments. Your request (show 2 fields instead of all) means that you need to have the new display (if you don't want the current Info set studio/builder_forms.php?page=fields&module=bx_persons&object=bx_person&display=bx_person_view) with this 2 fields. 

How to create Form Displays, add records to sys_form_displays table:

• display_name - name of the Form Display, in the format: form object name, underscore, internal identifier or nothing; for example: bx_group_add - for displaying group adding form, bx_group_edit - for displaying group editing form
• module - module name this display belongs to, it must be associated with name field in sys_modules table.
• object - form object name from sys_objects_form table this Form Display belongs to.
• title - Form Display title to display in studio forms builder.
• view_mode - display form as read-only.