Add OML definitions from OsmoBTS

Change-Id: I9c3bc15662949654e7bba6aad5488c69ee7d0c45
Related: OS#1615
diff --git a/include/osmocom/gsm/abis_nm.h b/include/osmocom/gsm/abis_nm.h
index 04bca43..14dbc08 100644
--- a/include/osmocom/gsm/abis_nm.h
+++ b/include/osmocom/gsm/abis_nm.h
@@ -34,6 +34,7 @@
 const char *abis_nm_avail_name(uint8_t avail);
 const char *abis_nm_test_name(uint8_t test);
 extern const struct tlv_definition abis_nm_osmo_att_tlvdef;
+extern const struct tlv_definition abis_nm_att_tlvdef_ipa;
 
 /*! \brief write a human-readable OML header to the debug log
  *  \param[in] ss Logging sub-system