linux-user: Fix compilation failure

Fix compilation failures for linux-user targets following recent
migration related commits bd2fa51f and 43487c67.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1372362818-4740-1-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>