ia64: Add export.h to arch/ia64 specific files as required

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/ia64/kernel/dma-mapping.c b/arch/ia64/kernel/dma-mapping.c
index f2c1600..7f79162 100644
--- a/arch/ia64/kernel/dma-mapping.c
+++ b/arch/ia64/kernel/dma-mapping.c
@@ -1,4 +1,5 @@
 #include <linux/dma-mapping.h>
+#include <linux/export.h>
 
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly;