arm64: dts: fsl-ls1012a-frdm: add spi-uart device

This patch adds spi-uart controller  to LS1012A-FRDM board dts.
Device is equipped in SC16IS740 from NXP.
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1012a-frdm.dts

@@ -7,6 +7,7 @@
  */
 /dts-v1/;
 
+#include <dt-bindings/interrupt-controller/irq.h>
 #include "fsl-ls1012a.dtsi"
 
 / {
@@ -57,6 +58,26 @@ simple-audio-card,codec {
 	};
 };
 
+&dspi {
+	bus-num = <0>;
+	status = "okay";
+
+	serial@0 {
+		compatible = "nxp,sc16is740";
+		reg = <0>;
+		spi-max-frequency = <4000000>;
+		clocks = <&sc16is7xx_clk>;
+		interrupt-parent = <&gpio1>;
+		interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+
+		sc16is7xx_clk: clock-sc16is7xx {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <24000000>;
+		};
+	};
+};
+
 &duart0 {
 	status = "okay";
 };