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/statfs.c b/fs/statfs.c
index 2aa6a22..43e6b6f 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -1,5 +1,5 @@
 #include <linux/syscalls.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/mount.h>