gianfar: Only process completed frames

If the LAST bit is not set in the RxBD, it's possible we're processing
an incomplete frame, which is bad.  While we're at it, add a constant
for the error bitmask, so the whole if-clause fits on one line,
and is more legible.

Signed-off-by: Dai Haruki <dai.haruki@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index 5b8991d..fcfa1bd 100644
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -340,6 +340,9 @@
 #define RXBD_OVERRUN		0x0002
 #define RXBD_TRUNCATED		0x0001
 #define RXBD_STATS		0x01ff
+#define RXBD_ERR		(RXBD_LARGE | RXBD_SHORT | RXBD_NONOCTET 	\
+				| RXBD_CRCERR | RXBD_OVERRUN			\
+				| RXBD_TRUNCATED)
 
 /* Rx FCB status field bits */
 #define RXFCB_VLN		0x8000