arm64: dts: marvell: cn9131-db: drop unneeded flash address/size-cells

Flash node uses single "partition" node to describe partitions, so
remove deprecated address/size-cells properties to also fix dtc W=1
warnings:

  cn9131-db.dtsi:140.10-163.4: Warning (avoid_unnecessary_addr_size): /cp1/config-space@f4000000/spi@700680/flash@0: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

Author: krzk

arch/arm64/boot/dts/marvell/cn9131-db.dtsi

@@ -138,8 +138,6 @@
 	reg = <0x700680 0x50>;
 
 	flash@0 {
-		#address-cells = <0x1>;
-		#size-cells = <0x1>;
 		compatible = "jedec,spi-nor";
 		reg = <0x0>;
 		/* On-board MUX does not allow higher frequencies */