dt-bindings: mfd: ti,j721e-system-controller: Add clock property

Add a pattern property for clock-controller, also update the example
with a clock-controller node
Signed-off-by: Rahul T R <r-ravikumar@ti.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220530101031.11357-2-r-ravikumar@ti.com

Documentation/devicetree/bindings/mfd/ti,j721e-system-controller.yaml

@@ -48,6 +48,12 @@ patternProperties:
     description:
       This is the SERDES lane control mux.
 
+  "^clock-controller@[0-9a-f]+$":
+    type: object
+    $ref: /schemas/clock/ti,am654-ehrpwm-tbclk.yaml#
+    description:
+      Clock provider for TI EHRPWM nodes.
+
 required:
   - compatible
   - reg
@@ -79,5 +85,11 @@ examples:
                 <0x40c0 0x3>, <0x40c4 0x3>, <0x40c8 0x3>, <0x40cc 0x3>;
                 /* SERDES4 lane0/1/2/3 select */
         };
+
+        clock-controller@4140 {
+            compatible = "ti,am654-ehrpwm-tbclk", "syscon";
+            reg = <0x4140 0x18>;
+            #clock-cells = <1>;
+        };
     };
 ...