Documentation: devicetree: Adapteva vendor prefix

Cc: Andreas Olofsson <andreas@adapteva.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -6,6 +6,7 @@ using them to avoid name-space collisions.
 abilis	Abilis Systems
 active-semi	Active-Semi International Inc
 ad	Avionic Design GmbH
+adapteva	Adapteva, Inc.
 adi	Analog Devices, Inc.
 aeroflexgaisler	Aeroflex Gaisler AB
 ak	Asahi Kasei Corp.