Add a new osmo_rtp_set_source_desc() function to set the RTCP SDES items

This allows the users of libosmotrau to set the content of the SDES
items to something more useful than their compile-time defaults.

Change-Id: Ice794f9e0c6caeea1c67520c12efbfa375d1fb82
Related: OS#2701
diff --git a/include/osmocom/trau/osmo_ortp.h b/include/osmocom/trau/osmo_ortp.h
index 578b1cb..5fb2960 100644
--- a/include/osmocom/trau/osmo_ortp.h
+++ b/include/osmocom/trau/osmo_ortp.h
@@ -100,5 +100,8 @@
 				uint32_t *recv_packets, uint32_t *recv_octets,
 				uint32_t *recv_lost, uint32_t *last_jitter);
 
+void osmo_rtp_set_source_desc(struct osmo_rtp_socket *rs, const char *cname,
+				const char *name, const char *email, const char *phone,
+				const char *loc, const char *tool, const char *note);
 
 #endif /* _OSMO_ORTP_H */