greybus: interface: device_id belongs to the interface

While introducing bundles, the device_id also got moved to the bundle,
whereas it identifies an interface block to the AP.

Move it back to interface instead of bundle.

Calls to gb_bundle(s)_init() are dropped as connections will be
initialized while they are created now, as device_id will be valid.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>