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/async.c b/kernel/async.c
index 4c2843c..80b74b88 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -51,7 +51,7 @@
 #include <linux/async.h>
 #include <linux/atomic.h>
 #include <linux/ktime.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/slab.h>