ag71xx: Reduce NAPI weight to 32.

Qualcomm claims this reduces cache misses. Original commit message below:

From: Ben Menchaca <[email protected]>
Date: Tue, 11 Jun 2013 12:18:46 -0500
Subject: [ag71xx] reduce NAPI weight

In an attempt to increase our cache warmth, we are decreasing NAPI.
This increases the warmth of the reused SKBs.

Signed-off-by: Ben Menchaca <[email protected]>
Signed-off-by: Rosen Penev <[email protected]>

target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h

@@ -40,7 +40,12 @@
 #define AG71XX_DRV_NAME		"ag71xx"
 #define AG71XX_DRV_VERSION	"0.5.35"
 
-#define AG71XX_NAPI_WEIGHT	64
+/*
+ * For our NAPI weight bigger does *NOT* mean better - it means more
+ * D-cache misses and lots more wasted cycles than we'll ever
+ * possibly gain from saving instructions.
+ */
+#define AG71XX_NAPI_WEIGHT	32
 #define AG71XX_OOM_REFILL	(1 + HZ/10)
 
 #define AG71XX_INT_ERR	(AG71XX_INT_RX_BE | AG71XX_INT_TX_BE)