MAINTAINERS: VIRTIO I2C loses a maintainer, gains a reviewer

Conghui Chen left, welcome Jian as reviewer.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: "Chen, Jian Jun" <jian.jun.chen@intel.com>