arm64: dts: amlogic: Fix SPI NOR flash node name for ODROID N2/N2+

Fix the schema warning: "spi-flash@0: $nodename:0: 'spi-flash@0' does
 not match '^flash(@.*)?$'" from jedec,spi-nor.yaml

Fixes: a084eaf3 ("arm64: dts: meson-g12b-odroid-n2: add SPIFC controller node")
Reviewed-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NAlexander Stein <alexander.stein@mailbox.org>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20211026182813.900775-3-alexander.stein@mailbox.org

arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dtsi

@@ -609,7 +609,7 @@
 	pinctrl-0 = <&nor_pins>;
 	pinctrl-names = "default";
 
-	mx25u64: spi-flash@0 {
+	mx25u64: flash@0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "mxicy,mx25u6435f", "jedec,spi-nor";