rsl: add rsl_act_type_name()

Change-Id: Ie90c76d8aef42d5e2c9be94f4b206d4994e305f8
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index d597f10..9667ea0 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -276,6 +276,7 @@
 rsl_rll_push_l3;
 rsl_rll_simple;
 rsl_rlm_cause_name;
+rsl_act_type_names;
 
 rxlev2dbm;
 rxlev_stat_dump;