of: documentation: Add vendor prefix for Tronfy

Tronfy is an emerging brand in China specializing in Home Theater
solutions for the normal consumers.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -222,6 +222,7 @@ toradex	Toradex AG
 toshiba	Toshiba Corporation
 toumaz	Toumaz
 tplink	TP-LINK Technologies Co., Ltd.
+tronfy	Tronfy
 truly	Truly Semiconductors Limited
 usi	Universal Scientific Industrial Co., Ltd.
 v3	V3 Semiconductor