of: Add vendor prefix for Ortus Technology Co., Ltd.

Add Ortus Technology Co., Ltd. to the list of device tree vendor prefixes.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>