Instead of using a custom offloading interface, users can use
`NET_SOCKET_REGISTER` macro to register custom socket API provider. This
solution removes a limitation, that only one offloaded interface can be
registered and that it cannot be used together with native IP stack.
The only exception remainig are DNS releated operations -
`getaddrinfo`/`freeaddrinfo`, which, when offloaded, have to be
registered specifically.
Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
bea1093e62