dt-bindings: Add vendor prefix for Linksys

Linksys (http://www.linksys.com/us/) is a vendor of networking products
mostly for use by home and small business user. The brand is currently
owned by Belkin International, Inc. (http://www.belkin.com/us/).

The vendor prefix linksys is already used by various supported boards.
Signed-off-by: NRalph Sennhauser <ralph.sennhauser@gmail.com>
Signed-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -177,6 +177,7 @@ lenovo	Lenovo Group Ltd.
 lg	LG Corporation
 licheepi	Lichee Pi
 linaro	Linaro Limited
+linksys	Belkin International, Inc. (Linksys)
 linux	Linux-specific binding
 lltc	Linear Technology Corporation
 lsi	LSI Corp. (LSI Logic)