add osmo_classmark_* API

osmo-bsc and osmo-msc implement identical Classmark structures. It makes sense
to define once near the gsm48 protocol definitions.

Also move along some generic Classmark API from osmo-msc.

Change-Id: Ifd27bab0380f7ad0c44c719aa6c8bd62cf7b034c
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index ea8c9be..3cfe6a7 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -580,5 +580,12 @@
 osmo_lu_type_names;
 osmo_cm_service_type_names;
 
+osmo_classmark_is_r99;
+osmo_classmark1_is_r99;
+osmo_classmark2_is_r99;
+osmo_classmark_supports_a5;
+osmo_classmark_a5_name;
+osmo_classmark_update;
+
 local: *;
 };