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.c b/drivers/spi/spi-dw.c
index 296d94f..082458d 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -19,6 +19,7 @@
 
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
+#include <linux/module.h>
 #include <linux/highmem.h>
 #include <linux/delay.h>
 #include <linux/slab.h>