OMAPFB: fix compilation warnings due to missing include

Fix warnings similar to this by including module.h:

drivers/video/omap/dispc.c:276:1: warning: data definition has no type
or storage class
drivers/video/omap/dispc.c:276:1: warning: type defaults to 'int' in
declaration of 'EXPORT_SYMBOL'
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap/dispc.c

@@ -19,6 +19,7 @@
  * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
 #include <linux/vmalloc.h>