arm: Add export.h to ARM specific files as required.

These files all make use of one of the EXPORT_SYMBOL variants
or the THIS_MODULE macro.  So they will need <linux/export.h>

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/arch/arm/mach-davinci/board-dm646x-evm.c b/arch/arm/mach-davinci/board-dm646x-evm.c
index 337c45e..e574d7f 100644
--- a/arch/arm/mach-davinci/board-dm646x-evm.c
+++ b/arch/arm/mach-davinci/board-dm646x-evm.c
@@ -31,6 +31,7 @@
 #include <linux/mtd/nand.h>
 #include <linux/mtd/partitions.h>
 #include <linux/clk.h>
+#include <linux/export.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>