powerpc: move device_to_mask() to dma-mapping.h

Move device_to_mask() to dma-mapping.h because we need to use it from
outside dma_64.c in a later patch.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/dma_64.c

@@ -15,15 +15,6 @@
  * Generic iommu implementation
  */
 
-static inline unsigned long device_to_mask(struct device *dev)
-{
-	if (dev->dma_mask && *dev->dma_mask)
-		return *dev->dma_mask;
-	/* Assume devices without mask can take 32 bit addresses */
-	return 0xfffffffful;
-}
-
-
 /* Allocates a contiguous real buffer and creates mappings over it.
  * Returns the virtual address of the buffer and sets dma_handle
  * to the dma address (mapping) of the first page.

include/asm-powerpc/dma-mapping.h

@@ -45,6 +45,15 @@ extern void __dma_sync_page(struct page *page, unsigned long offset,
 #endif /* ! CONFIG_NOT_COHERENT_CACHE */
 
 #ifdef CONFIG_PPC64
+
+static inline unsigned long device_to_mask(struct device *dev)
+{
+	if (dev->dma_mask && *dev->dma_mask)
+		return *dev->dma_mask;
+	/* Assume devices without mask can take 32 bit addresses */
+	return 0xfffffffful;
+}
+
 /*
  * DMA operations are abstracted for G5 vs. i/pSeries, PCI vs. VIO
  */