arm64: dts: qcom: apq8096-db820c: add PM8994 pin function

The bindings require that every pin configuration comes with 'function'
property.  Add such to PM8994 GPIO5.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220507194913.261121-8-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/apq8096-db820c.dts

@@ -558,6 +558,7 @@ &pm8994_gpios {
 	ls_exp_gpio_f: pm8994-gpio5-state {
 		pinconf {
 			pins = "gpio5";
+			function = PMIC_GPIO_FUNC_NORMAL;
 			output-low;
 			power-source = <2>; // PM8994_GPIO_S4, 1.8V
 		};