mm: Map most files to use export.h instead of module.h

The files changed within are only using the EXPORT_SYMBOL
macro variants.  They are not using core modular infrastructure
and hence don't need module.h but only the export.h header.

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

mm/page-writeback.c

@@ -12,7 +12,7 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/spinlock.h>
 #include <linux/fs.h>
 #include <linux/mm.h>