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-ti-ssp.c b/drivers/spi/spi-ti-ssp.c
index 7963c60..3f6f6e8 100644
--- a/drivers/spi/spi-ti-ssp.c
+++ b/drivers/spi/spi-ti-ssp.c
@@ -22,6 +22,7 @@
 #include <linux/err.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/spi/spi.h>
 #include <linux/mfd/ti_ssp.h>