dt-bindings: iio: frequency: adf4377: add clk provider

Add support for clock provider.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/frequency/adi,adf4377.yaml

@@ -40,6 +40,12 @@ properties:
     items:
       - const: ref_in
 
+  '#clock-cells':
+    const: 0
+
+  clock-output-names:
+    maxItems: 1
+
   chip-enable-gpios:
     description:
       GPIO that controls the Chip Enable Pin.
@@ -97,6 +103,8 @@ examples:
             spi-max-frequency = <10000000>;
             clocks = <&adf4377_ref_in>;
             clock-names = "ref_in";
+            #clock-cells = <0>;
+            clock-output-names = "adf4377";
         };
     };
 ...