of: Add Chunghwa Picture Tubes Ltd. vendor prefix

Chunghwa Picture Tubes Ltd. isn't listed on the stock exchange, so use
the generic "chunghwa" as vendor prefix.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -19,6 +19,7 @@ brcm	Broadcom Corporation
 cavium	Cavium, Inc.
 cdns	Cadence Design Systems Inc.
 chrp	Common Hardware Reference Platform
+chunghwa	Chunghwa Picture Tubes Ltd.
 cirrus	Cirrus Logic, Inc.
 cortina	Cortina Systems, Inc.
 dallas	Maxim Integrated Products (formerly Dallas Semiconductor)