blackfin: Add export.h to files using EXPORT_SYMBOL/THIS_MODULE

These particular files were just assuming that module.h was
somehow in the include paths.  Give them the more minimalist
header file explicitly.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/blackfin/mm/init.c b/arch/blackfin/mm/init.c
index f8435cd..78daae0 100644
--- a/arch/blackfin/mm/init.c
+++ b/arch/blackfin/mm/init.c
@@ -8,6 +8,7 @@
 #include <linux/swap.h>
 #include <linux/bootmem.h>
 #include <linux/uaccess.h>
+#include <linux/export.h>
 #include <asm/bfin-global.h>
 #include <asm/pda.h>
 #include <asm/cplbinit.h>