socket: Introduce API osmo_sock_multiaddr_get_ip_and_port()

This API will be used internally by osmo_sock_multiaddr_get_name_buf()
in a follow-up patch.
This API can also be used directly by user who wish to obtain a list of
local/remote IP addresses and port from an SCTP socket.

Related: SYS#6636
Related: OS#5581
Change-Id: I19d560ab4aadec18a4c0f94115675ec1d7ab14d7
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index 30c4927..ffbbd2f 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -436,6 +436,7 @@
 osmo_sock_mcast_ttl_set;
 osmo_sock_multiaddr_add_local_addr;
 osmo_sock_multiaddr_del_local_addr;
+osmo_sock_multiaddr_get_ip_and_port;
 osmo_sock_set_dscp;
 osmo_sock_set_priority;
 osmo_sock_unix_init;