dt-bindings: Add QiShenglong vendor prefix

Add vendor prefix for Shenzhen QiShenglong Industrialist Co., Ltd.
QiShenglong is a Chinese manufacturer of handheld gaming consoles, most of
which run (very old) versions of Linux.
QiShenglong is known as Hamy.

Signed-off-by: Artjom Vejsel <akawolf0@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210725221527.1771892-2-akawolf0@gmail.com