kernel-doc: fix some errors

- Delete fs.xml from DOCBOOKS to fix an error.
     Commit e3ff797c added fs.xml to DOCBOOKS
     but missed to add doc/DocBook/fs.tmpl.
  - Fix the location of include guard in include/linker_lists.h.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Abraham Varricatt <abraham.varricatt@vvdntech.com>
Acked-by: Simon Glass <sjg@chromium.org>