devicetree: Add Fujitsu Ltd. vendor prefix

The vendor prefix for Fujitsu is used in the tree, but it's
still missing from the documentation, so add it. Fujitsu Ltd.
is a japanese ICT company, http://www.fujitsu.com

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -107,6 +107,7 @@ firefly	Firefly
 focaltech	FocalTech Systems Co.,Ltd
 friendlyarm	Guangzhou FriendlyARM Computer Tech Co., Ltd
 fsl	Freescale Semiconductor
+fujitsu	Fujitsu Ltd.
 ge	General Electric Company
 geekbuying	GeekBuying
 gef	GE Fanuc Intelligent Platforms Embedded Systems, Inc.