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/pci/switch/switchtec.c

@@ -1373,10 +1373,10 @@ static int switchtec_init_pci(struct switchtec_dev *stdev,
 	if (ioread32(&stdev->mmio_mrpc->dma_ver) == 0)
 		return 0;
 
-	stdev->dma_mrpc = dma_zalloc_coherent(&stdev->pdev->dev,
-					      sizeof(*stdev->dma_mrpc),
-					      &stdev->dma_mrpc_dma_addr,
-					      GFP_KERNEL);
+	stdev->dma_mrpc = dma_alloc_coherent(&stdev->pdev->dev,
+					     sizeof(*stdev->dma_mrpc),
+					     &stdev->dma_mrpc_dma_addr,
+					     GFP_KERNEL);
 	if (stdev->dma_mrpc == NULL)
 		return -ENOMEM;