greybus: bundle: rename bundle devices

Rename bundle devices so that the new device names become
"<bus_id>-<intf_id>.<bundle_id>", where bus_id is the dynamically
allocated host-device bus id and intf_id the svc-allocated interface
id.

Using a period (.) rather than a colon (:) makes dev-messages easier to
read as as those already add a colon after the device name, for example:

	greybus 1-4.15: failed to connect cport: -22

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>