ocfs2: fix sparse non static symbol warning

Fixes the following sparse warning:

  fs/ocfs2/stack_user.c:930:32: warning:
   symbol 'ocfs2_ls_ops' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>