dt-bindings: vendor-prefixes: Add Xnano

Xnano is a Chinese TV box brand, but not much more is publicly known.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -1125,6 +1125,8 @@ patternProperties:
     description: Shenzhen Xinpeng Technology Co., Ltd
   "^xlnx,.*":
     description: Xilinx
+  "^xnano,.*":
+    description: Xnano
   "^xunlong,.*":
     description: Shenzhen Xunlong Software CO.,Limited
   "^xylon,.*":