dt-bindings: add vendor prefix for Theobroma Systems

Theobroma Systems is a design house specialized in embedded systems
and a manufacturer of system-on-modules.

Signed-off-by: Klaus Goger <klaus.goger@theobroma-systems.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -342,6 +342,7 @@ tpo	TPO
 tronfy	Tronfy
 tronsmart	Tronsmart
 truly	Truly Semiconductors Limited
+tsd	Theobroma Systems Design und Consulting GmbH
 tyan	Tyan Computer Corporation
 ucrobotics	uCRobotics
 udoo	Udoo