drivers/of: Add module.h to of_spi.c

This file really needs the full module.h header file present, but
was just getting it implicitly before.  Fix it up in advance so we
avoid build failures once the cleanup commit is present.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/of/of_spi.c

@@ -6,6 +6,7 @@
  * tree.
  */
 
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/device.h>
 #include <linux/spi/spi.h>