s390/pci_dma: remove memset from dma_alloc

Get rid of a useless memset from dma_alloc. Users of dma_alloc who want
zero initialized memory can get it by specifying __GFP_ZERO or use one
of the zalloc variants.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_dma.c

@@ -391,8 +391,6 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 		return NULL;
 
 	pa = page_to_phys(page);
-	memset((void *) pa, 0, size);
-
 	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
 	if (dma_mapping_error(dev, map)) {
 		free_pages(pa, get_order(size));