of: Add United Radiant Technology Corporation vendor prefix

Add vendor prefix for United Radiant Technology Corporation,
a provider of liquid crystal display technologies.
Signed-off-by: NMaciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -240,6 +240,7 @@ tplink	TP-LINK Technologies Co., Ltd.
 tronfy	Tronfy
 truly	Truly Semiconductors Limited
 upisemi	uPI Semiconductor Corp.
+urt	United Radiant Technology Corporation
 usi	Universal Scientific Industrial Co., Ltd.
 v3	V3 Semiconductor
 variscite	Variscite Ltd.