DT: Add vendor prefix for Emerging Display Technologies

Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -26,6 +26,7 @@ cortina	Cortina Systems, Inc.
 dallas	Maxim Integrated Products (formerly Dallas Semiconductor)
 davicom	DAVICOM Semiconductor, Inc.
 denx	Denx Software Engineering
+edt	Emerging Display Technologies
 emmicro	EM Microelectronic
 epfl	Ecole Polytechnique Fédérale de Lausanne
 epson	Seiko Epson Corp.