I/OAT: tcp_dma_copybreak default value dependent on I/OAT version

I/OAT DMA performance tuning showed different optimal values of
tcp_dma_copybreak for different I/OAT versions (4096 for 1.2 and 2048
for 2.0).  This patch lets ioatdma driver set tcp_dma_copybreak value
according to these results.

[dan.j.williams@intel.com: remove some ifdefs]
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index da57296..ece5a0e 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -1581,6 +1581,8 @@
 	if (err)
 		goto err_self_test;
 
+	ioat_set_tcp_copy_break(device);
+
 	dma_async_device_register(&device->common);
 
 	INIT_DELAYED_WORK(&device->work, ioat_dma_chan_watchdog);