ixp4xx: add back the patch for avoiding dma bounce buffers for network buffers, which was lost on the kernel upgrade to 2.6.32. fixes ath9k and improves other drivers' performance on boards with >64M ram

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@20708 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/ixp4xx/patches-2.6.32/600-skb_avoid_dmabounce.patch

@@ -0,0 +1,13 @@
+--- a/net/core/skbuff.c
++++ b/net/core/skbuff.c
+@@ -264,6 +264,10 @@ struct sk_buff *__alloc_skb(unsigned int
+ 	if (!skb)
+ 		goto out;
+ 
++#ifdef CONFIG_ARCH_IXP4XX
++	gfp_mask |= GFP_DMA;
++#endif
++
+ 	size = SKB_DATA_ALIGN(size);
+ 	data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
+ 			gfp_mask, node);