mailmap: Add missing email address

I've been using that email address for contributions for a while but it
seems I never added it to mailmap.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230531133724.133872-1-maxime@cerno.tech