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>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 49583c5..4d18fca 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -33,6 +33,7 @@
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_VIRT_CPU_ACCOUNTING
+	select ARCH_HAS_DMA_MARK_CLEAN
 	select ARCH_HAS_SG_CHAIN
 	select VIRT_TO_BUS
 	select ARCH_DISCARD_MEMBLOCK