dt-bindings: pinctrl: apple,pinctrl: Add apple,t6020-pinctrl compatible

After discussion with the devicetree maintainers we agreed to not extend
lists with the generic compatible "apple,pinctrl" anymore [1]. Use
"apple,t8103-pinctrl" as fallback compatible as it is the SoC the driver
and bindings were written for.

The M2 Pro/Max/Ultra SoCs use the same pinctrl hardware, so just add its
per-SoC compatible using the new base as fallback.

[1]: https://lore.kernel.org/asahi/12ab93b7-1fc2-4ce0-926e-c8141cfe81bf@kernel.org/

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Janne Grunau <j@jannau.net>

Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml

@@ -16,17 +16,22 @@ description: |
 
 properties:
   compatible:
-    items:
-      - enum:
-          - apple,s5l8960x-pinctrl
-          - apple,t7000-pinctrl
-          - apple,s8000-pinctrl
-          - apple,t8010-pinctrl
-          - apple,t8015-pinctrl
-          - apple,t8103-pinctrl
-          - apple,t8112-pinctrl
-          - apple,t6000-pinctrl
-      - const: apple,pinctrl
+    oneOf:
+      - items:
+          - const: apple,t6020-pinctrl
+          - const: apple,t8103-pinctrl
+      - items:
+          # Do not add additional SoC to this list.
+          - enum:
+              - apple,s5l8960x-pinctrl
+              - apple,t7000-pinctrl
+              - apple,s8000-pinctrl
+              - apple,t8010-pinctrl
+              - apple,t8015-pinctrl
+              - apple,t8103-pinctrl
+              - apple,t8112-pinctrl
+              - apple,t6000-pinctrl
+          - const: apple,pinctrl
 
   reg:
     maxItems: 1