arm64: dts: qcom: sc7280-idp: add amp pin config function

Bindings expect each pin config to come with a "function" property:

  sc7280-crd-r3.dtb: pinctrl@f100000: amp-en-state: 'oneOf' conditional failed, one must be fixed:
    'function' is a required property
    'bias-pull-down', 'drive-strength', 'pins' do not match any of the regexes: '-pins$', 'pinctrl-[0-9]+'
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221230135645.56401-9-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/sc7280-idp.dtsi

@@ -732,6 +732,7 @@ &sdc2_data {
 &tlmm {
 	amp_en: amp-en-state {
 		pins = "gpio63";
+		function = "gpio";
 		bias-pull-down;
 		drive-strength = <2>;
 	};