arm64: dts: db820c: add support to LS-UART0

This patch adds support to 4 pin UART0 on LS expansion connector.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

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

@@ -16,6 +16,7 @@
 / {
 	aliases {
 		serial0 = &blsp2_uart1;
+		serial1 = &blsp2_uart2;
 	};
 
 	chosen {
@@ -30,5 +31,13 @@ serial@75b0000 {
 			pinctrl-0 = <&blsp2_uart1_2pins_default>;
 			pinctrl-1 = <&blsp2_uart1_2pins_sleep>;
 		};
+
+		serial@75b1000 {
+			label = "LS-UART0";
+			status = "okay";
+			pinctrl-names = "default", "sleep";
+			pinctrl-0 = <&blsp2_uart2_4pins_default>;
+			pinctrl-1 = <&blsp2_uart2_4pins_sleep>;
+		};
 	};
 };