devicetree: bindings: add Conexant vendor prefix

Use "cnxt" since it once was the stock ticker of Conexant.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -35,6 +35,7 @@ chrp	Common Hardware Reference Platform
 chunghwa	Chunghwa Picture Tubes Ltd.
 cirrus	Cirrus Logic, Inc.
 cnm	Chips&Media, Inc.
+cnxt	Conexant Systems, Inc.
 cortina	Cortina Systems, Inc.
 crystalfontz	Crystalfontz America, Inc.
 dallas	Maxim Integrated Products (formerly Dallas Semiconductor)