devicetree: bindings: Add vendor prefix for Topeet.

Add TOPEET, a ARM devlopment board vendor in China mainland.
Signed-off-by: Randy Li <ayaka@soulik.info>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -269,6 +269,7 @@ technologic	Technologic Systems
 thine	THine Electronics, Inc.
 ti	Texas Instruments
 tlm	Trusted Logic Mobility
+topeet  Topeet
 toradex	Toradex AG
 toshiba	Toshiba Corporation
 toumaz	Toumaz