[IA64] build fix for scatterlist

include/scsi/scsi_eh.h:79: error: field `sense_sgl' has incomplete type

x86 resolves this by including scatterlist.h from dma-mapping.h which
seems as good a place as any.
Signed-off-by: Tony Luck <tony.luck@intel.com>

include/asm-ia64/dma-mapping.h

@@ -6,6 +6,7 @@
  *	David Mosberger-Tang <davidm@hpl.hp.com>
  */
 #include <asm/machvec.h>
+#include <asm/scatterlist.h>
 
 #define dma_alloc_coherent	platform_dma_alloc_coherent
 /* coherent mem. is cheap */