dt-bindings: vendor-prefixes: Add mstar vendor prefix

Add prefix for MStar Semiconductor, Inc.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>