Socket network interface tests were failing due to DICONNECTED event
being advertised, where GLOBAL_UP was expected. It turned out that
nanostack receives two events: APPL_EVENT_CONNECT and
APPL_BACKHAUL_INTERFACE_PHY_UP. The second attempt to connect obviously
returns errors, but it also causes events to be sent out to the
application. The second attempt should not take place in case the
bootstrap is already started.
I also fixed two reports being sent with DISCONNECT status, while they
are actually something else.
Make Nanostack an OnboardNetworkInterface, implementing
add_ethernet_interface so it can use EMAC drivers.
Can now be used via EthernetInterface, and be the system's default
network stack.
Legacy support for NanostackEthernetInterface retained. Some
restructuring of mesh interface code to fit into the
OnboardNetworkStack:::Interface system.