Add serialized method support so that explicit Mutex can be
avoided

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Message-id: 1449804086-3464-2-git-send-email-zhaoshenglong@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>