of: Add Okaya Electric America vendor prefix

This patch adds vendor prefix for Okaya Electronic America, a provider
of LCD modules and display technologies.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>