dt-bindings: gpu: apple,agx: Add agx-{g14s,g14c,g14d} compatibles

Add compatibles for the GPU variants found on Apple's M2 Pro/Max/Ultra
SoCs.

Reviewed-by: Neal Gompa <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Janne Grunau <[e-mail]>

Documentation/devicetree/bindings/gpu/apple,agx.yaml

···
           - apple,agx-g13g
           - apple,agx-g13s
           - apple,agx-g14g
+          - apple,agx-g14s
       - items:
           - enum:
               - apple,agx-g13c
               - apple,agx-g13d
           - const: apple,agx-g13s
+      - items:
+          - enum:
+              - apple,agx-g14c
+              - apple,agx-g14d
+          - const: apple,agx-g14s
 
   reg:
     items: