gsup: add osmo_gsup_message_type_name()

Change-Id: Ic29b588b72893821d73fe90ecc16c6bf78d5a360
diff --git a/include/osmocom/gsm/gsup.h b/include/osmocom/gsm/gsup.h
index e2912a6..04b31d0 100644
--- a/include/osmocom/gsm/gsup.h
+++ b/include/osmocom/gsm/gsup.h
@@ -95,6 +95,11 @@
 #define OSMO_GSUP_IS_MSGT_ERROR(msgt)   (((msgt) & 0b00000011) == 0b01)
 #define OSMO_GSUP_TO_MSGT_ERROR(msgt)   (((msgt) & 0b11111100) | 0b01)
 
+extern const struct value_string osmo_gsup_message_type_names[];
+static inline const char *
+osmo_gsup_message_type_name(enum osmo_gsup_message_type val)
+{	return get_value_string(osmo_gsup_message_type_names, val); }
+
 enum osmo_gsup_cancel_type {
 	OSMO_GSUP_CANCEL_TYPE_UPDATE		= 1, /* on wire: 0 */
 	OSMO_GSUP_CANCEL_TYPE_WITHDRAW		= 2, /* on wire: 1 */