ortp: Export statistics for the bts or similar

We might want to know how many things arrived at the BTS and
ortp is already counting for us. We don't intend to use RTCP
so I am not sure what the last "sender report" is and how
accurate the jitter is.
diff --git a/include/osmocom/trau/osmo_ortp.h b/include/osmocom/trau/osmo_ortp.h
index 2d32b02..c02cca8 100644
--- a/include/osmocom/trau/osmo_ortp.h
+++ b/include/osmocom/trau/osmo_ortp.h
@@ -79,4 +79,10 @@
 				int subsys, int level,
 				const char *pfx);
 
+void osmo_rtp_socket_stats(struct osmo_rtp_socket *rs,
+				uint32_t *sent_packets, uint32_t *sent_octets,
+				uint32_t *recv_packets, uint32_t *recv_octets,
+				uint32_t *recv_lost, uint32_t *last_jitter);
+
+
 #endif /* _OSMO_ORTP_H */