caif: set traffic class for caif packets

Set traffic class for CAIF packets, based on socket
priority, CAIF protocol type, or type of message.

Traffic class mapping for different packet types:
 - control:       TC_PRIO_CONTROL;
 - flow control:  TC_PRIO_CONTROL;
 - at:            TC_PRIO_CONTROL;
 - rfm:           TC_PRIO_INTERACTIVE_BULK;
 - other sockets: equals to socket's TC;
 - network data:  no change.

Signed-off-by: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/caif/cfpkt.h

@@ -188,11 +188,18 @@ struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt);
  */
 void *cfpkt_tonative(struct cfpkt *pkt);
 
-
 /*
  * Returns packet information for a packet.
  * pkt Packet to get info from;
  * @return Packet information
  */
 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt);
+
+/** cfpkt_set_prio - set priority for a CAIF packet.
+ *
+ * @pkt: The CAIF packet to be adjusted.
+ * @prio: one of TC_PRIO_ constants.
+ */
+void cfpkt_set_prio(struct cfpkt *pkt, int prio);
+
 #endif				/* CFPKT_H_ */