mfd: Add module.h to the implicit drivers/mfd users

With the pending module.h cleanup, these files will fail to compile,
unless they explicitly call out the include of this file.

[omap-usb-host addition courtesy of Anand Gadiyar <gadiyar@ti.com>]

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

drivers/mfd/wm8400-core.c

@@ -12,6 +12,7 @@
  *
  */
 
+#include <linux/module.h>
 #include <linux/bug.h>
 #include <linux/err.h>
 #include <linux/i2c.h>