of: Add vendor prefix for Cirrus Logic

This patch adds a device tree vendor prefix for Cirrus Logic, Inc.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -14,6 +14,7 @@ bosch	Bosch Sensortec GmbH
 brcm	Broadcom Corporation
 cavium	Cavium, Inc.
 chrp	Common Hardware Reference Platform
+cirrus	Cirrus Logic, Inc.
 cortina	Cortina Systems, Inc.
 dallas	Maxim Integrated Products (formerly Dallas Semiconductor)
 denx	Denx Software Engineering