mv643xx_eth: shrink default receive and transmit queue sizes

Since the size of the receive queue is directly related to the data
cache footprint of the driver (between refilling a receive ring entry
with a fresh skb and receiving a packet in that entry, queue_size - 1
other skbs will have been touched), shrink the default receive queue
size to a saner number of entries, as 400 is definite overkill for
almost all workloads.

While we are at it, trim the default transmit queue size a bit as well.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

drivers/net/mv643xx_eth.c

@@ -165,8 +165,8 @@ static char mv643xx_eth_driver_version[] = "1.3";
 #define FORCE_LINK_PASS				(1 << 1)
 #define SERIAL_PORT_ENABLE			(1 << 0)
 
-#define DEFAULT_RX_QUEUE_SIZE		400
-#define DEFAULT_TX_QUEUE_SIZE		800
+#define DEFAULT_RX_QUEUE_SIZE		128
+#define DEFAULT_TX_QUEUE_SIZE		256
 
 
 /*