I noticed that in the latest version, the copyright string is still
2022, even though 2023 is halfway through.  This patch fixes that and
fixes the documentation along with it.

Signed-off-by: Enze Li <lienze@kylinos.cn>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230525064345.1152801-1-lienze@kylinos.cn
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>