page_to_phys() always returns a multiple of PAGE_SIZE

BugLink: http://bugs.launchpad.net/bugs/1558624Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from commit bdb97e91)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

arch/s390/pci/pci_dma.c

@@ -366,8 +366,7 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 	pa = page_to_phys(page);
 	memset((void *) pa, 0, size);
 
-	map = s390_dma_map_pages(dev, page, pa % PAGE_SIZE,
-				 size, DMA_BIDIRECTIONAL, NULL);
+	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, NULL);
 	if (dma_mapping_error(dev, map)) {
 		free_pages(pa, get_order(size));
 		return NULL;