ARM: mvebu: kirkwood: Add compatible property to "partitions" node

As of commit e488ca9f ("doc: dt: mtd: partitions: add compatible
property to "partitions" node"), the "partitions" subnode of an SPI
FLASH device node must have a compatible property. The partitions are no
longer detected if it is not present.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>

arch/arm/boot/dts/kirkwood-pogoplug-series-4.dts

@@ -131,6 +131,7 @@
 	chip-delay = <40>;
 	status = "okay";
 	partitions {
+		compatible = "fixed-partitions";
 		#address-cells = <1>;
 		#size-cells = <1>;