[POWERPC] Replace a few #defines with empty inline functions

...so that GCC doesn't complain about unused variables in the
callers of these.
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-powerpc/dma-mapping.h

@@ -249,8 +249,12 @@ dma_map_single(struct device *dev, void *ptr, size_t size,
 	return virt_to_bus(ptr);
 }
 
-/* We do nothing. */
-#define dma_unmap_single(dev, addr, size, dir)	((void)0)
+static inline void dma_unmap_single(struct device *dev, dma_addr_t dma_addr,
+				    size_t size,
+				    enum dma_data_direction direction)
+{
+	/* We do nothing. */
+}
 
 static inline dma_addr_t
 dma_map_page(struct device *dev, struct page *page,
@@ -264,8 +268,12 @@ dma_map_page(struct device *dev, struct page *page,
 	return page_to_bus(page) + offset;
 }
 
-/* We do nothing. */
-#define dma_unmap_page(dev, handle, size, dir)	((void)0)
+static inline void dma_unmap_page(struct device *dev, dma_addr_t dma_address,
+				  size_t size,
+				  enum dma_data_direction direction)
+{
+	/* We do nothing. */
+}
 
 static inline int
 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
@@ -284,8 +292,12 @@ dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 	return nents;
 }
 
-/* We don't do anything here. */
-#define dma_unmap_sg(dev, sg, nents, dir)	((void)0)
+static inline void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+				int nhwentries,
+				enum dma_data_direction direction)
+{
+	/* We don't do anything here. */
+}
 
 #endif /* CONFIG_PPC64 */