devicetree: Document Wolfson prefix

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index e855278..2c1b2cb 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -37,4 +37,5 @@
 sirf	SiRF Technology, Inc.
 stericsson	ST-Ericsson
 ti	Texas Instruments
+wlf	Wolfson Microelectronics
 xlnx	Xilinx