cross-tree: phase out dma_zalloc_coherent()

We already need to zero out memory for dma_alloc_coherent(), as such
using dma_zalloc_coherent() is superflous. Phase it out.

This change was generated with the following Coccinelle SmPL patch:

@ replace_dma_zalloc_coherent @
expression dev, size, data, handle, flags;
@@

-dma_zalloc_coherent(dev, size, handle, flags)
+dma_alloc_coherent(dev, size, handle, flags)

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: re-ran the script on the latest tree]
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/net/wireless/ralink/rt2x00/rt2x00mmio.c

@@ -119,9 +119,9 @@ static int rt2x00mmio_alloc_queue_dma(struct rt2x00_dev *rt2x00dev,
 	/*
 	 * Allocate DMA memory for descriptor and buffer.
 	 */
-	addr = dma_zalloc_coherent(rt2x00dev->dev,
-				   queue->limit * queue->desc_size, &dma,
-				   GFP_KERNEL);
+	addr = dma_alloc_coherent(rt2x00dev->dev,
+				  queue->limit * queue->desc_size, &dma,
+				  GFP_KERNEL);
 	if (!addr)
 		return -ENOMEM;