mpc83xx: Fix the UEC driver bug of QE

The patch prevents the GCC tool chain from striping useful code for
optimization. It will make UEC ethernet driver workable, Otherwise the
UEC will fail in tx when you are using gcc4.x. but the driver can work
when using gcc3.4.3.

CHANGELOG

*Prevent the GCC from striping code for optimization, Otherwise the UEC
will tx failed when you are using gcc4.x.

Signed-off-by: Dave Liu <daveliu@freescale.com>

drivers/qe/uec.c

@@ -1122,7 +1122,7 @@ static int uec_send(struct eth_device* dev, volatile void *buf, int len)
 	uec_private_t		*uec;
 	ucc_fast_private_t	*uccf;
 	volatile qe_bd_t	*bd;
-	volatile u16		status;
+	u16			status;
 	int			i;
 	int			result = 0;
 
@@ -1131,7 +1131,7 @@ static int uec_send(struct eth_device* dev, volatile void *buf, int len)
 	bd = uec->txBd;
 
 	/* Find an empty TxBD */
-	for (i = 0; BD_STATUS(bd) & TxBD_READY; i++) {
+	for (i = 0; bd->status & TxBD_READY; i++) {
 		if (i > 0x100000) {
 			printf("%s: tx buffer not ready\n", dev->name);
 			return result;
@@ -1150,13 +1150,11 @@ static int uec_send(struct eth_device* dev, volatile void *buf, int len)
 	ucc_fast_transmit_on_demand(uccf);
 
 	/* Wait for buffer to be transmitted */
-	status = BD_STATUS(bd);
-	for (i = 0; status & TxBD_READY; i++) {
+	for (i = 0; bd->status & TxBD_READY; i++) {
 		if (i > 0x100000) {
 			printf("%s: tx error\n", dev->name);
 			return result;
 		}
-		status = BD_STATUS(bd);
 	}
 
 	/* Ok, the buffer be transimitted */
@@ -1171,12 +1169,12 @@ static int uec_recv(struct eth_device* dev)
 {
 	uec_private_t		*uec = dev->priv;
 	volatile qe_bd_t	*bd;
-	volatile u16		status;
+	u16			status;
 	u16			len;
 	u8			*data;
 
 	bd = uec->rxBd;
-	status = BD_STATUS(bd);
+	status = bd->status;
 
 	while (!(status & RxBD_EMPTY)) {
 		if (!(status & RxBD_ERROR)) {
@@ -1190,7 +1188,7 @@ static int uec_recv(struct eth_device* dev)
 		BD_LENGTH_SET(bd, 0);
 		BD_STATUS_SET(bd, status | RxBD_EMPTY);
 		BD_ADVANCE(bd, status, uec->p_rx_bd_ring);
-		status = BD_STATUS(bd);
+		status = bd->status;
 	}
 	uec->rxBd = bd;