Add Shannon Zhao as the maintainer for the ARM ACPI Subsystem.

Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1433248318-6076-1-git-send-email-shannon.zhao@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>