MAINTAINERS: Update HISILICON DRM entries

Signed-off-by: Rongrong Zou <zourongrong@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Xinliang Liu <xinliang.liu@linaro.org>
Acked-by: Sean Paul <seanpaul@chromium.org>