caif: Replace BUG_ON with WARN_ON.

BUG_ON is too strict in a number of circumstances,
use WARN_ON instead. Protocol errors should not halt the system.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c
index 23406e6..9341a2d 100644
--- a/drivers/net/caif/caif_serial.c
+++ b/drivers/net/caif/caif_serial.c
@@ -261,7 +261,7 @@
 		skb_pull(skb, tty_wr);
 		if (skb->len == 0) {
 			struct sk_buff *tmp = skb_dequeue(&ser->head);
-			BUG_ON(tmp != skb);
+			WARN_ON(tmp != skb);
 			if (in_interrupt())
 				dev_kfree_skb_irq(skb);
 			else
@@ -305,7 +305,7 @@
 
 	ser = tty->disc_data;
 	BUG_ON(ser == NULL);
-	BUG_ON(ser->tty != tty);
+	WARN_ON(ser->tty != tty);
 	handle_tx(ser);
 }