of: Add Avionic Design vendor prefix

This commit adds a device tree vendor prefix for Avionic Design GmbH.

Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -3,6 +3,7 @@ Device tree binding vendor prefix registry.  Keep list in alphabetical order.
 This isn't an exhaustive list, but you should add new prefixes to it before
 using them to avoid name-space collisions.
 
+ad	Avionic Design GmbH
 adi	Analog Devices, Inc.
 amcc	Applied Micro Circuits Corporation (APM, formally AMCC)
 apm	Applied Micro Circuits Corporation (APM)