staging: pi433: overlay: Convert to sugar syntax

Using overlay sugar syntax makes the DTS overlay files easier to read
(and write).
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200221122133.32024-4-geert+renesas@glider.beSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/Documentation/devicetree/pi433-overlay.dts

@@ -4,10 +4,9 @@
 
 / {
 	compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
+};
 
-	fragment@0 {
-		target = <&spi0>;
-		__overlay__ {
+&spi0 {
 	#address-cells = <1>;
 	#size-cells = <0>;
 	status = "okay";
@@ -21,22 +20,16 @@ spidev@1{
 		reg = <1>;
 		status = "disabled";
 	};
-		};
-	};
+};
 
-	fragment@1 {
-		target = <&gpio>;
-		__overlay__ {
+&gpio {
 	pi433_pins: pi433_pins {
 		brcm,pins = <7 25 24>;
 		brcm,function = <0 0 0>; // in in in
 	};
-		};
-	};
+};
 
-	fragment@2 {
-		target = <&spi0>;
-		__overlay__ {
+&spi0 {
 	#address-cells = <1>;
 	#size-cells = <0>;
 	status = "okay";
@@ -52,6 +45,4 @@ pi433: pi433@0 {
 		DIO1-gpio = <&gpio 25 0>;
 		DIO2-gpio = <&gpio  7 0>;
 	};
-		};
-	};
 };