osmo_io: Log error message in case call-backs incompatible with mode

Change-Id: I50ba6a76c0144f249d67488874a6c4edf01ec6f2
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index 72a6038..072efee 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -264,6 +264,7 @@
 osmo_iofd_set_name;
 osmo_iofd_get_priv_nr;
 osmo_iofd_init;
+osmo_iofd_mode_names;
 osmo_iofd_ops;
 osmo_iofd_register;
 osmo_iofd_sendto_msgb;