[PATCH] ppc64: fix failure return codes from {pci,vio}_alloc_consistent()

From: Olof Johansson <olof@austin.ibm.com>

A bug snuck in during the rewrite of ppc64 IOMMU code.  When a
{pci,vio}_alloc_consistent() call fails, DMA_ERROR_CODE is returned instead
of NULL.

arch/ppc64/kernel/pci_iommu.c

@@ -83,7 +83,7 @@ void *pci_iommu_alloc_consistent(struct pci_dev *hwdev, size_t size,
 	if (order >= IOMAP_MAX_ORDER) {
 		printk("PCI_DMA: pci_alloc_consistent size too large: 0x%lx\n",
 			size);
-		return (void *)DMA_ERROR_CODE;
+		return NULL;
 	}
 
 	tbl = devnode_table(hwdev); 

arch/ppc64/kernel/vio.c

@@ -504,8 +504,8 @@ void *vio_alloc_consistent(struct vio_dev *dev, size_t size,
  	/* Client asked for way to much space.  This is checked later anyway */
 	/* It is easier to debug here for the drivers than in the tce tables.*/
  	if(order >= IOMAP_MAX_ORDER) {
- 		printk("VIO_DMA: vio_alloc_consistent size to large: 0x%lx \n", size);
- 		return (void *)DMA_ERROR_CODE;
+ 		printk("VIO_DMA: vio_alloc_consistent size too large: 0x%lx \n", size);
+ 		return NULL;
  	}
 
 	tbl = dev->iommu_table;