ARM: zynq: Convert at25 binding to new description on zc770-xm013

The Linux commit f8f79fa6bb25 ("dt-bindings: at25: convert the binding
document to yaml") converted binding to yaml and 3 deprecated properties
pop up.

The patch is fixing these warnings:
.../zynq-zc770-xm013.dt.yaml: eeprom@2: 'pagesize' is a required property
.../zynq-zc770-xm013.dt.yaml: eeprom@2: 'size' is a required property
.../zynq-zc770-xm013.dt.yaml: eeprom@2: 'address-width' is a required property
>From schema: .../Documentation/devicetree/bindings/eeprom/at25.yaml

by converting them to new binding.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/be2c1125d98386033e182012eb08986924707a76.1606397101.git.michal.simek@xilinx.com

arch/arm/dts/zynq-zc770-xm013.dts

@@ -68,13 +68,12 @@
 	num-cs = <4>;
 	is-decoded-cs = <0>;
 	eeprom: eeprom@2 {
-		at25,byte-len = <8192>;
-		at25,addr-mode = <2>;
-		at25,page-size = <32>;
-
 		compatible = "atmel,at25";
 		reg = <2>;
 		spi-max-frequency = <1000000>;
+		size = <8192>;
+		address-width = <16>;
+		pagesize = <32>;
 	};
 };