caif: Use link layer MTU instead of fixed MTU

Previously CAIF supported maximum transfer size of ~4050.
The transfer size is now calculated dynamically based on the
link layers mtu size.

Signed-off-by: Sjur Braendeland@stericsson.com
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/caif/cfserl.c b/net/caif/cfserl.c
index 965c5ba..a11fbd6 100644
--- a/net/caif/cfserl.c
+++ b/net/caif/cfserl.c
@@ -14,7 +14,8 @@
 #define container_obj(layr) ((struct cfserl *) layr)
 
 #define CFSERL_STX 0x02
-#define CAIF_MINIUM_PACKET_SIZE 4
+#define SERIAL_MINIUM_PACKET_SIZE 4
+#define SERIAL_MAX_FRAMESIZE 4096
 struct cfserl {
 	struct cflayer layer;
 	struct cfpkt *incomplete_frm;
@@ -119,8 +120,8 @@
 		/*
 		 * Frame error handling
 		 */
-		if (expectlen < CAIF_MINIUM_PACKET_SIZE
-		    || expectlen > CAIF_MAX_FRAMESIZE) {
+		if (expectlen < SERIAL_MINIUM_PACKET_SIZE
+		    || expectlen > SERIAL_MAX_FRAMESIZE) {
 			if (!layr->usestx) {
 				if (pkt != NULL)
 					cfpkt_destroy(pkt);