add some new switch properties to support nic backends, specifically tap backends
rocker: use standard vendor and pci id

Better to change pci id and vendor id early on to something meaningful.
Default qemu emulated hw ids will do.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>