arm64: dts: apq8016-sbc: make 1.8v available on LS expansion

96boards mezzanine boards on LS expansion require 1.8v as per 96boards
specifications, so enable the corresponding regulators and make them
always-on.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi

@@ -230,9 +230,14 @@ l14 {
 		regulator-max-microvolt = <3337000>;
 	};
 
+	/**
+	 * 1.8v required on LS expansion
+	 * for mezzanine boards
+	 */
 	l15 {
 		regulator-min-microvolt = <1750000>;
 		regulator-max-microvolt = <3337000>;
+		regulator-always-on;
 	};
 
 	l16 {