Doc: devicetree: bindings: Add vendor prefix entry - lwn

This patch adds entry for LWN - the Liebherr-Werk Nenzing GmbH company to
vendor-prefixes.txt file.
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -164,6 +164,7 @@ lg	LG Corporation
 linux	Linux-specific binding
 lltc	Linear Technology Corporation
 lsi	LSI Corp. (LSI Logic)
+lwn	Liebherr-Werk Nenzing GmbH
 macnica	Macnica Americas
 marvell	Marvell Technology Group Ltd.
 maxim	Maxim Integrated Products