[PATCH] ide: fix ide_toggle_bounce() to not try to bounce if we have an IOMMU

The following patch fixes a crash caused by attempting to bounce buffer
when an IDE CD-ROM is used on a machine with an IO-MMU. [At least, this
patch fixes things so I can use my IDE CD-ROM behind an ns87415 on a 
HP PA-RISC workstation.]
Signed-off-by: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-lib.c

@@ -410,10 +410,10 @@ void ide_toggle_bounce(ide_drive_t *drive, int on)
 {
 	u64 addr = BLK_BOUNCE_HIGH;	/* dma64_addr_t */
 
-	if (on && drive->media == ide_disk) {
-		if (!PCI_DMA_BUS_IS_PHYS)
+	if (!PCI_DMA_BUS_IS_PHYS) {
 		addr = BLK_BOUNCE_ANY;
-		else if (HWIF(drive)->pci_dev)
+	} else if (on && drive->media == ide_disk) {
+		if (HWIF(drive)->pci_dev)
 			addr = HWIF(drive)->pci_dev->dma_mask;
 	}