video: Add export.h for THIS_MODULE/EXPORT_SYMBOL to drivers/video

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: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/video/via/via-gpio.c b/drivers/video/via/via-gpio.c
index ab53418..d69cfef 100644
--- a/drivers/video/via/via-gpio.c
+++ b/drivers/video/via/via-gpio.c
@@ -10,6 +10,7 @@
 #include <linux/platform_device.h>
 #include <linux/via-core.h>
 #include <linux/via-gpio.h>
+#include <linux/export.h>
 
 /*
  * The ports we know about.  Note that the port-25 gpios are not