ARM: dts: sunxi: Fix the SPI NOR node names

According to the SPI NOR bindings, the flash node names are supposed to
be flash@<address>. Let's fix our users to use that new scheme.

Signed-off-by: Maxime Ripard <[e-mail]>
Acked-by: Jernej Skrabec <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm/boot/dts/sun8i-v3-sl631.dtsi

···
 &spi0 {
 	status = "okay";
 
-	spi-flash@0 {
+	flash@0 {
 		reg = <0>;
 		compatible = "jedec,spi-nor";
 		spi-max-frequency = <50000000>;

arch/arm/boot/dts/sunxi-libretech-all-h3-it.dtsi

···
 &spi0 {
 	status = "okay";
 
-	spiflash@0 {
+	flash@0 {
 		compatible = "jedec,spi-nor";
 		reg = <0>;
 		spi-max-frequency = <50000000>;

arch/arm64/boot/dts/allwinner/sun50i-a64-orangepi-win.dts

···
 &spi0 {
 	status = "okay";
 
-	spi-flash@0 {
+	flash@0 {
 		compatible = "mxicy,mx25l1606e", "jedec,spi-nor";
 		reg = <0>;
 		spi-max-frequency = <80000000>;