arm64: dts: armada-3720-espressobin: wire up spi flash

This is the storage the machine boots from by default. The partitioning
is taken from the U-Boot that is shipped with the board. There is some
more space on the flash that isn't used.
Tested-by: NGregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: NEllie Reeves <ellierevves@gmail.com>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGregory CLEMENT <gregory.clement@bootlin.com>

arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts

@@ -63,6 +63,33 @@
 	status = "okay";
 };
 
+&spi0 {
+	status = "okay";
+
+	flash@0 {
+		reg = <0>;
+		compatible = "winbond,w25q32dw", "jedec,spi-flash";
+		spi-max-frequency = <104000000>;
+		m25p,fast-read;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "uboot";
+				reg = <0 0x180000>;
+			};
+
+			partition@180000 {
+				label = "ubootenv";
+				reg = <0x180000 0x10000>;
+			};
+		};
+	};
+};
+
 /* Exported on the micro USB connector J5 through an FTDI */
 &uart0 {
 	pinctrl-names = "default";