dt-bindings: gpu: mali-bifrost: Fix power-domain-names validation

Commit ("dt-bindings: gpu: mali-bifrost: Add Mediatek MT8183")
incorrectly introduced power domain names for MT8183, causing
validation issues.

Add power-domain-names to the base schema, allowing a maximum of
five elements; since platforms having a single power domain don't
need any actual domain name, disallow that for each sub-schema.

Fixes: a7a596cd ("dt-bindings: gpu: mali-bifrost: Add Mediatek MT8183")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230316102041.210269-4-angelogioacchino.delregno@collabora.com

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

@@ -65,6 +65,10 @@ properties:
     minItems: 1
     maxItems: 5
 
+  power-domain-names:
+    minItems: 2
+    maxItems: 5
+
   resets:
     minItems: 1
     maxItems: 3
@@ -112,6 +116,7 @@ allOf:
       properties:
         power-domains:
           maxItems: 1
+        power-domain-names: false
       required:
         - resets
   - if:
@@ -136,6 +141,7 @@ allOf:
             - const: bus_ace
         power-domains:
           maxItems: 1
+        power-domain-names: false
         resets:
           minItems: 3
         reset-names:
@@ -186,6 +192,7 @@ allOf:
             - const: bus
         power-domains:
           maxItems: 1
+        power-domain-names: false
       required:
         - clock-names