dt-bindings: gpu: mali-midgard: add samsung exynos 5420 compatible

Add "samsung,exynos5420-mali" binding
Signed-off-by: Marian Mihailescu <mihailescu2m@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml

@@ -18,6 +18,10 @@ properties:
           - enum:
              - samsung,exynos5250-mali
           - const: arm,mali-t604
+      - items:
+          - enum:
+             - samsung,exynos5420-mali
+          - const: arm,mali-t628
       - items:
           - enum:
              - allwinner,sun50i-h6-mali
@@ -38,7 +42,6 @@ properties:
           - const: arm,mali-t860
 
           # "arm,mali-t624"
-          # "arm,mali-t628"
           # "arm,mali-t830"
           # "arm,mali-t880"