dt-bindings: display/panel: Add KOE tx14d24vm1bpa display description

This commit adds documentation entry description for KOE's 5.7" display.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190515160428.6114-1-lukma@denx.de