dt-bindings: iio: stm32: dfsdm: fix dtbs warnings on dfsdm audio port

Fix warnings on DFSDM dtbs check
Unevaluated properties are not allowed ('dfsdm-dai' was unexpected)
'port' does not match any of the regexes: 'pinctrl-[0-9]+'

Fixes: 11183ac0 ("dt-bindings: stm32: convert dfsdm to json-schema")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20240618115912.706912-1-olivier.moysan@foss.st.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml

@@ -246,6 +246,10 @@ patternProperties:
                     From common IIO binding. Used to pipe external sigma delta
                     modulator or internal ADC output to DFSDM channel.
 
+                port:
+                  $ref: /schemas/sound/audio-graph-port.yaml#
+                  unevaluatedProperties: false
+
               required:
                 - compatible
                 - "#sound-dai-cells"