microblaze: Add export.h to arch/microblaze files as required

For access to the EXPORT_SYMBOL variants and THIS_MODULE macros.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/microblaze/kernel/dma.c b/arch/microblaze/kernel/dma.c
index 393e6b2..b159b8a 100644
--- a/arch/microblaze/kernel/dma.c
+++ b/arch/microblaze/kernel/dma.c
@@ -10,6 +10,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/gfp.h>
 #include <linux/dma-debug.h>
+#include <linux/export.h>
 #include <asm/bug.h>
 #include <asm/cacheflush.h>