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

The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include <linux/module.h>
  +#include <linux/export.h>

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/kernel/cred.c b/kernel/cred.c
index bb55d05..5791612 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -8,7 +8,7 @@
  * as published by the Free Software Foundation; either version
  * 2 of the Licence, or (at your option) any later version.
  */
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/cred.h>
 #include <linux/slab.h>
 #include <linux/sched.h>