dt-bindings: iio: adc: nxp,lpc3220-adc: allow clocks property

Allow clocks property to fix below CHECK_DTB warning:
  arch/arm/boot/dts/nxp/lpc/lpc3250-ea3250.dtb: adc@40048000 (nxp,lpc3220-adc): 'clocks' does not match any of the regexes: 'pinctrl-[0-9]+'

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250624201302.2515391-1-Frank.Li@nxp.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: nxpfrankli

Documentation/devicetree/bindings/iio/adc/nxp,lpc3220-adc.yaml

@@ -22,6 +22,9 @@ properties:
   interrupts:
     maxItems: 1
 
+  clocks:
+    maxItems: 1
+
   vref-supply: true
 
   "#io-channel-cells":