abis_nm: Add abis_nm_admin_name() API

Similar APIs exist for opstate and availability status.

This patch does not break backward compatibility because osmo-bsc still
requires direct use of the structure in get_string_value().

Change-Id: Ieace734aaff3f07606113feddde65b75202d96d6
diff --git a/include/osmocom/gsm/abis_nm.h b/include/osmocom/gsm/abis_nm.h
index e031ee1..dd7ba0d 100644
--- a/include/osmocom/gsm/abis_nm.h
+++ b/include/osmocom/gsm/abis_nm.h
@@ -28,9 +28,16 @@
 const char *abis_nm_event_type_name(uint8_t cause);
 const char *abis_nm_severity_name(uint8_t cause);
 extern const struct tlv_definition abis_nm_att_tlvdef;
+
 const char *abis_nm_opstate_name(uint8_t os);
 const char *abis_nm_avail_name(uint8_t avail);
 const char *abis_nm_test_name(uint8_t test);
+/*! Get human-readable string for OML administrative state */
+static inline const char *abis_nm_admin_name(uint8_t admin)
+{
+	return get_value_string(abis_nm_adm_state_names, admin);
+}
+
 extern const struct tlv_definition abis_nm_osmo_att_tlvdef;
 extern const struct tlv_definition abis_nm_att_tlvdef_ipa;