04.80: Deprecate gsm0480_create_ussd_resp()

In July 2018 in commit Ide240279240322f643e142229eb7829f538c6314 we
introduced the successor gsm0480_gen_ussd_resp_7bit(), which is also
what both libosmogsm-internal code as well as osmo-hlr have been ported
to.  For some reason it wasn't marked deprecated back then.

Change-Id: Iff4c91b5b98a73d9a30aa42f6b2a1ebcc8a45343
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 3ae591a..1d5cde9 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -821,6 +821,7 @@
  * not only the FACILITY value, but the full L3 message including message header
  * and FACILITY IE Tag+Length.
  */
+OSMO_DEPRECATED("Use gsm0480_gen_ussd_resp_7bit() instead")
 struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const char *text)
 {
 	struct msgb *msg;