ethernet: remove support for default interface ip config

Support for default IpConfiguration was removed from EthernetConfigStore
in change Ifb82a5d7fa13d17ea8fd3a42a19cd020cb95e26a. This code has since
been a noop.

Test: atest EthernetTracker
Bug: 236280707
Change-Id: I6b9a2fa1af5f6ab7454d523d28daf4ee383d3560
2 files changed