MAINTAINERS: update mail address for Weiwei Li

MAINTAINERS: update mail address for Weiwei Li

My Iscas mail account will be disabled soon, change to my personal
gmail account.

Signed-off-by: Weiwei Li <liwei1518@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231030081607.115118-2-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>