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>
diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 64bdeeb..dedb7f6 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -8,6 +8,7 @@
 #include <linux/seq_file.h>
 #include <linux/uaccess.h>
 #include <linux/fs.h>
+#include <linux/module.h>
 #include <linux/debugfs.h>
 #include <linux/platform_device.h>