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/lib/raid6/algos.c b/lib/raid6/algos.c
index b595f56..8b02f60 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/raid/pq.h>
+#include <linux/module.h>
 #ifndef __KERNEL__
 #include <sys/mman.h>
 #include <stdio.h>