dt-bindings: arm: samsung: Document E850-96 board binding

Add binding for the WinLink E850-96 board, which is based on Samsung
Exynos850 SoC.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20211217161549.24836-5-semen.protsenko@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

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

@@ -205,6 +205,12 @@ properties:
               - samsung,jackpotlte              # Samsung Galaxy A8 (2018)
           - const: samsung,exynos7885
 
+      - description: Exynos850 based boards
+        items:
+          - enum:
+              - winlink,e850-96                 # WinLink E850-96
+          - const: samsung,exynos850
+
       - description: Exynos Auto v9 based boards
         items:
           - enum: