Change API to convey marker bit

Previously RTP receive callback ignored Marker bit from RTP
headers. Extend API to include it explicitly.

Change-Id: I3c2b6365d8a51bf98805614e07344d2639875fde
Related: OS#1750
diff --git a/include/osmocom/trau/osmo_ortp.h b/include/osmocom/trau/osmo_ortp.h
index 7c2a5cb..1c0b223 100644
--- a/include/osmocom/trau/osmo_ortp.h
+++ b/include/osmocom/trau/osmo_ortp.h
@@ -55,7 +55,7 @@
 
 	/*! \brief callback for incoming data */
 	void (*rx_cb)(struct osmo_rtp_socket *rs, const uint8_t *payload,
-		      unsigned int payload_len);
+		      unsigned int payload_len, bool marker);
 
 	/*! \brief Receive user timestamp, to be incremented by user */
 	uint32_t rx_user_ts;