spi: Add module.h to implicit users in drivers/spi

We are clipping down the presence of module.h, since it was
everywhere.  If you really need it, you better call it out,
as per this changeset.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/spi/spi-gpio.c

@@ -18,6 +18,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/gpio.h>