powerpc: Bring in some changes made to arch/ppc and include/asm-ppc64

Recent commits upstream have changed files which are currently
duplicated in arch/powerpc and include/asm-powerpc.  This updates
them with the corresponding changes.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/iommu.h b/include/asm-powerpc/iommu.h
index d096faf..f80ec8d 100644
--- a/include/asm-powerpc/iommu.h
+++ b/include/asm-powerpc/iommu.h
@@ -88,7 +88,7 @@
 		int nelems, enum dma_data_direction direction);
 
 extern void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size,
-		dma_addr_t *dma_handle, unsigned int __nocast flag);
+		dma_addr_t *dma_handle, gfp_t flag);
 extern void iommu_free_coherent(struct iommu_table *tbl, size_t size,
 		void *vaddr, dma_addr_t dma_handle);
 extern dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr,