dt-bindings: clock: mpfs-clkcfg: Add pic64gx compatibility

pic64gx has a clock controller compatible with mpfs-clkcfg. Don't permit
the deprecated configuration that was never supported for this SoC.

Signed-off-by: Pierre-Henry Moussay <pierre-henry.moussay@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20260113-glue-justifier-566ffab2ffd3@spud
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>

Author: Pierre-Henry Moussay

Documentation/devicetree/bindings/clock/microchip,mpfs-clkcfg.yaml

@@ -19,7 +19,11 @@ description: |
 
 properties:
   compatible:
-    const: microchip,mpfs-clkcfg
+    oneOf:
+      - items:
+          - const: microchip,pic64gx-clkcfg
+          - const: microchip,mpfs-clkcfg
+      - const: microchip,mpfs-clkcfg
 
   reg:
     oneOf:
@@ -69,6 +73,16 @@ required:
   - clocks
   - '#clock-cells'
 
+if:
+  properties:
+    compatible:
+      contains:
+        const: microchip,pic64gx-clkcfg
+then:
+  properties:
+    reg:
+      maxItems: 1
+
 additionalProperties: false
 
 examples: