Documentation/x86: Fix path in zero-page.txt

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Martin Mares <mj@ucw.cz>
Link: http://lkml.kernel.org/r/1422689004-13318-1-git-send-email-kuleshovmail@gmail.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>