svc: add support for generating network link up events

Add basic support for generating a link up event after the
hotplug event has been sent. For now, we hardcoded the
interface and device ID. This needs reworked to parse
the manifest and assign a device ID per interface ID and
subject to the rules of address translation where we will
allocate additional device IDs for each range of 32 cports
above the first 32 cports handled by the first device ID.

Signed-off-by: Matt Porter <mporter@linaro.org>