IA64: sg chaining support

This updates the ia64 iommu/pci dma mappers to sg chaining.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/asm-ia64/scatterlist.h b/include/asm-ia64/scatterlist.h
index a452ea2..7d5234d 100644
--- a/include/asm-ia64/scatterlist.h
+++ b/include/asm-ia64/scatterlist.h
@@ -30,4 +30,6 @@
 #define sg_dma_len(sg)		((sg)->dma_length)
 #define sg_dma_address(sg)	((sg)->dma_address)
 
+#define	ARCH_HAS_SG_CHAIN
+
 #endif /* _ASM_IA64_SCATTERLIST_H */