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_hsi.c b/drivers/net/caif/caif_hsi.c
index a85b29e..0a4fc62 100644
--- a/drivers/net/caif/caif_hsi.c
+++ b/drivers/net/caif/caif_hsi.c
@@ -933,7 +933,7 @@
 
 		/* Create HSI frame. */
 		len = cfhsi_tx_frm(desc, cfhsi);
-		BUG_ON(!len);
+		WARN_ON(!len);
 
 		/* Set up new transfer. */
 		res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);