powerpc/iommu: remove the mapping_error dma_map_ops method

The powerpc iommu code already returns (~(dma_addr_t)0x0) on mapping
failures, so we can switch over to returning DMA_MAPPING_ERROR and let
the core dma-mapping code handle the rest.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/include/asm/iommu.h

@@ -143,8 +143,6 @@ struct scatterlist;
 
 #ifdef CONFIG_PPC64
 
-#define IOMMU_MAPPING_ERROR		(~(dma_addr_t)0x0)
-
 static inline void set_iommu_table_base(struct device *dev,
 					struct iommu_table *base)
 {
@@ -242,8 +240,6 @@ static inline int __init tce_iommu_bus_notifier_init(void)
 }
 #endif /* !CONFIG_IOMMU_API */
 
-int dma_iommu_mapping_error(struct device *dev, dma_addr_t dma_addr);
-
 #else
 
 static inline void *get_iommu_table_base(struct device *dev)