Documentation: Add EZchip vendor to binding list

Add EZchip to vendor prefixes list.
EZchip introduce the NPS platform for the ARC architecture.
Signed-off-by: Noam Camus <noamc@ezchip.com>
Acked-by: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>

Documentation/devicetree/bindings/arc/eznps.txt

+EZchip NPS Network Processor Platforms Device Tree Bindings
+---------------------------------------------------------------------------
+
+Appliance main board with NPS400 ASIC.
+
+Required root node properties:
+    - compatible = "ezchip,arc-nps";

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -86,6 +86,7 @@ eukrea  Eukréa Electromatique
 everest	Everest Semiconductor Co. Ltd.
 everspin	Everspin Technologies, Inc.
 excito	Excito
+ezchip	EZchip Semiconductor
 fcs	Fairchild Semiconductor
 firefly	Firefly
 focaltech	FocalTech Systems Co.,Ltd