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>
diff --git a/drivers/spi/spi-dw-pci.c b/drivers/spi/spi-dw-pci.c
index c5f37f0..f64250e 100644
--- a/drivers/spi/spi-dw-pci.c
+++ b/drivers/spi/spi-dw-pci.c
@@ -21,6 +21,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/module.h>
 
 #include "spi-dw.h"