dt-bindings: arm: samsung: Document exynosautov920 SADK board binding

Add binding for the ExynosAutov920 SADK(Samsung Automotive Development Kit)
board.
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Link: https://lore.kernel.org/r/20231115095609.39883-8-jaewon02.kim@samsung.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Documentation/devicetree/bindings/arm/samsung/samsung-boards.yaml

@@ -230,6 +230,12 @@ properties:
               - samsung,exynosautov9-sadk   # Samsung Exynos Auto v9 SADK
           - const: samsung,exynosautov9
 
+      - description: Exynos Auto v920 based boards
+        items:
+          - enum:
+              - samsung,exynosautov920-sadk   # Samsung Exynos Auto v920 SADK
+          - const: samsung,exynosautov920
+
 required:
   - compatible