dt-bindings: vendor-prefixes: Add Ultratronik

Ultratronik GmbH is a German electronics company:
https://www.ultratronik-ems.de/

Signed-off-by: Goran Rađenović <goran.radni@gmail.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250508143818.2574558-2-goran.radni@gmail.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -1607,6 +1607,8 @@ patternProperties:
     description: Universal Scientific Industrial Co., Ltd.
   "^usr,.*":
     description: U.S. Robotics Corporation
+  "^ultratronik,.*":
+    description: Ultratronik GmbH
   "^utoo,.*":
     description: Aigo Digital Technology Co., Ltd.
   "^v3,.*":