dma-mapping: move dma_mark_clean to dma-direct.h

And unlike the other helpers we don't require a <asm/dma-direct.h> as
this helper is a special case for ia64 only, and this keeps it as
simple as possible.

Signed-off-by: Christoph Hellwig <hch@lst.de>

arch/ia64/include/asm/dma.h

@@ -20,6 +20,4 @@ extern unsigned long MAX_DMA_ADDRESS;
 
 #define free_dma(x)
 
-void dma_mark_clean(void *addr, size_t size);
-
 #endif /* _ASM_IA64_DMA_H */