greybus: svc: move endo id and ap interface id to svc

Move endo_id and AP interface id to the svc device.

The endo abstraction is about to be removed, and these attributes are
arguable attributes of the svc anyway.

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