dt-bindings: mfd: apple,smc: Add t6020-smc compatible

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

SMC on Apple's M2 Pro/Max/Ultra SoCs is compatible with the existing
driver so add its per-SoC compatible with the new base compatible as
fallback used by the driver.

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

@@ -15,12 +15,17 @@ description:
 
 properties:
   compatible:
-    items:
-      - enum:
-          - apple,t6000-smc
-          - apple,t8103-smc
-          - apple,t8112-smc
-      - const: apple,smc
+    oneOf:
+      - items:
+          - const: apple,t6020-smc
+          - const: apple,t8103-smc
+      - items:
+          - enum:
+              # Do not add additional SoC to this list.
+              - apple,t6000-smc
+              - apple,t8103-smc
+              - apple,t8112-smc
+          - const: apple,smc
 
   reg:
     items: