via-velocity: Change DMA_LENGTH_DEF (from the VIA driver)

The VIA driver has changed the default for the DMA_LENGTH_DEF parameter.
Together with adaptive interrupt supression and NAPI support, this
improves performance quite a bit
Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/via-velocity.c

@@ -275,7 +275,7 @@ VELOCITY_PARAM(rx_thresh, "Receive fifo threshold");
 
 #define DMA_LENGTH_MIN  0
 #define DMA_LENGTH_MAX  7
-#define DMA_LENGTH_DEF  0
+#define DMA_LENGTH_DEF  6
 
 /* DMA_length[] is used for controlling the DMA length
    0: 8 DWORDs