i2c: add export.h to i2c-boardinfo.c for EXPORT_SYMBOL

With module.h being implicitly everywhere via device.h, the absence
of explicitly including something for EXPORT_SYMBOL went unnoticed.
Since we are heading to fix things up and clean module.h from the
device.h file, we need to explicitly include these files now.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

drivers/i2c/i2c-boardinfo.c

@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 #include <linux/rwsem.h>
 
 #include "i2c-core.h"