The current method for handling DAD directly tracks a DAD state for each
iface.
This does not reflect the fact that each individual IP has a separate
DAD state.
This also does not align with the logic in conn_mgr_initial_state, which
instead uses net_if_ipv6_get_global_addr(NET_ADDR_PREFERRED, ...).
Thus, the current approach falsely reports IPv6 ready when DAD adds
the link_addr, and also fails to report IPv6 ready if DAD is disabled.
This commit removes DAD tracking completely, and relies solely on
net_if_ipv6_get_global_addr(NET_ADDR_PREFERRED, ...), fixing both
problems, and simplifying the event tracking.
For consistency, slight modifications to IPv4 handling as well.
Signed-off-by: Georges Oates_Larsen <georges.larsen@nordicsemi.no>
068dc8ba6f