greybus: interface: Get manifest using Control protocol
Control protocol is ready to be used for fetching manifest. Lets do it.
This changes few things:
- Creates/initializes bundle/connection for control protocol initially
and skips doing the same later.
- Manifest is parsed at link-up now, instead of hotplug which was the
case earlier. This is because we need device_id (provided during
link-up) for registering bundle.
- Manifest is fetched using control protocol.