spi: nuvoton,npcm-fiu: Change spi-nor@0 name to flash@0

The node name for flash memories has been standardized to "flash@...".
Fix the example in nuvoton,npcm-fiu.txt accordingly.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20221031222559.199509-1-j.neuschaefer@gmx.netSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/nuvoton,npcm-fiu.txt

@@ -51,7 +51,7 @@ fiu3: spi@c00000000 {
 	clocks = <&clk NPCM7XX_CLK_AHB>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi3_pins>;
-	spi-nor@0 {
+	flash@0 {
 			...
 	};
 };