arm64: dts: qcom: pm6150l: Add missing include

Add missing include to make it compile.
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210923162204.21752-17-konrad.dybcio@somainline.org

arch/arm64/boot/dts/qcom/pm6150l.dtsi

 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2019, The Linux Foundation. All rights reserved.
 
+#include <dt-bindings/iio/qcom,spmi-vadc.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/spmi/spmi.h>