s390/pci: ensure page aligned dma start address

We don't have an architectural guarantee on the value of
the dma offset but rely on it to be at least page aligned.
Enforce page alignemt of start_dma.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_dma.c

@@ -469,6 +469,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
 	 * Also set zdev->end_dma to the actual end address of the usable
 	 * range, instead of the theoretical maximum as reported by hardware.
 	 */
+	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
 	zdev->iommu_size = min3((u64) high_memory,
 				ZPCI_TABLE_SIZE_RT - zdev->start_dma,
 				zdev->end_dma - zdev->start_dma + 1);