md: Add module.h to all files using it implicitly

A pending cleanup will mean that module.h won't be implicitly
everywhere anymore.  Make sure the modular drivers in md dir
are actually calling out for <module.h> explicitly in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 0eb08a4..0cf86cf 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -20,6 +20,7 @@
 
 #include <linux/blkdev.h>
 #include <linux/seq_file.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 #include "md.h"
 #include "raid0.h"