powerpc/swiotlb: Fix off by one in determining boundary of which ops to use

When we compare the devices DMA mask to the amount of memory we need to
make sure we treat the DMA mask as an address boundary.  For example if
the DMA_MASK(32) and we have 4G of memory we'd incorrectly set the dma
ops to swiotlb.  We need to add one to the dma mask when we convert it.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

arch/powerpc/kernel/dma-swiotlb.c

 /*
  * Contains routines needed to support swiotlb for ppc.
  *
- * Copyright (C) 2009 Becky Bruce, Freescale Semiconductor
+ * Copyright (C) 2009-2010 Freescale Semiconductor, Inc.
+ * Author: Becky Bruce
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
@@ -70,7 +71,7 @@ static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
 	sd->max_direct_dma_addr = 0;
 
 	/* May need to bounce if the device can't address all of DRAM */
-	if (dma_get_mask(dev) < lmb_end_of_DRAM())
+	if ((dma_get_mask(dev) + 1) < lmb_end_of_DRAM())
 		set_dma_ops(dev, &swiotlb_dma_ops);
 
 	return NOTIFY_DONE;