Manufacturer field is empty when adding a component template to a device type

[jeremystretch]

Environment

• Python version: 3.6.9
• NetBox version: 2.9.9

Steps to Reproduce

1. Add a new component template to an existing device type

Expected Behavior

The manufacturer field should show the device type's manufacturer.

Observed Behavior

The device type field is automatically populated, but the manufacturer field is blank. (This does not actually prevent the component template from being created, but may be confusing to the user.)