dt-bindings: vendor-prefix: add Wanchanglong Electronics Technology

Wanchanglong Electronics Technology is a company to provide LCD
modules.

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211016102232.202119-2-michael@amarulasolutions.com