dt-bindings: adc: axi-adc: add clocks property

Add a required clock property as we can't access the device registers if
the AXI bus clock is not properly enabled.

Note this clock is a very fundamental one that is typically enabled
pretty early during boot. Independently of that, we should really rely on
it to be enabled.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Fixes: 96553a44e9 ("dt-bindings: iio: adc: add bindings doc for AXI ADC driver")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240426-ad9467-new-features-v2-3-6361fc3ba1cc@analog.com
Cc: <Stable@ver.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml

@@ -28,6 +28,9 @@ properties:
   reg:
     maxItems: 1
 
+  clocks:
+    maxItems: 1
+
   dmas:
     maxItems: 1
 
@@ -48,6 +51,7 @@ required:
   - compatible
   - dmas
   - reg
+  - clocks
 
 additionalProperties: false
 
@@ -58,6 +62,7 @@ examples:
         reg = <0x44a00000 0x10000>;
         dmas = <&rx_dma 0>;
         dma-names = "rx";
+        clocks = <&axi_clk>;
         #io-backend-cells = <0>;
     };
 ...