docs: fix various Documentation/ paths in header files

Fix various Documentation/ paths in include/linux/.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index 7f62777..ddb7a97 100644
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -27,8 +27,8 @@
  *
  * configfs Copyright (C) 2005 Oracle.  All rights reserved.
  *
- * Please read Documentation/filesystems/configfs.txt before using the
- * configfs interface, ESPECIALLY the parts about reference counts and
+ * Please read Documentation/filesystems/configfs/configfs.txt before using
+ * the configfs interface, ESPECIALLY the parts about reference counts and
  * item destructors.
  */