powerpc: Call dma_debug_add_bus for PCI and VIO buses

The DMA API debug code has hooks to verify all DMA entries have been
freed at time of hot unplug. We need to call dma_debug_add_bus for
this to work.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/vio.h b/arch/powerpc/include/asm/vio.h
index b19adf7..df81cb7 100644
--- a/arch/powerpc/include/asm/vio.h
+++ b/arch/powerpc/include/asm/vio.h
@@ -44,6 +44,8 @@
  */
 #define VIO_CMO_MIN_ENT 1562624
 
+extern struct bus_type vio_bus_type;
+
 struct iommu_table;
 
 /*