ARM: dts: msm: Add scale-fn-type for batt_therm for QM215

Add the Scaling function type for the battery thermistor
for the QM215 hardware.

Change-Id: If468feab45af1603f730d0b01ebc26945c9d20d0

qcom/qm215-qrd.dtsi

@@ -1,4 +1,5 @@
 #include <dt-bindings/clock/qcom,rpmcc.h>
+#include <dt-bindings/iio/qcom,spmi-vadc.h>
 
 &blsp1_uart2 {
 	status = "ok"
@@ -28,6 +29,12 @@
 	status = "ok"
 };
 
+&pm8916_vadc {
+	batt_therm {
+		qcom,scale-fn-type = <ADC_SCALE_BATT_THERM_QRD_215>;
+	};
+};
+
 &soc {
 	gpio_keys {
 		compatible = "gpio-keys";