ganc: add value_strings for GAN message type and protocol discriminator
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 4583de8..80e1dc1 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -227,5 +227,8 @@
 tlv_parse_one;
 tvlv_att_def;
 
+gan_msgt_vals;
+gan_pdisc_vals;
+
 local: *;
 };