fs: reduce the use of module.h wherever possible

For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/fs/eventfd.c b/fs/eventfd.c
index d9a5917..dba15fe 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -16,7 +16,7 @@
 #include <linux/spinlock.h>
 #include <linux/anon_inodes.h>
 #include <linux/syscalls.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/kref.h>
 #include <linux/eventfd.h>