ARM: dts: wpcm450-supermicro-x9sci-ln4f: Add SPI flash

Add the BMC firmware flash to the devicetree, so that it can be accessed
from Linux.

Signed-off-by: Jonathan Neuschäfer <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Joel Stanley <[e-mail]>

arch/arm/boot/dts/nuvoton-wpcm450-supermicro-x9sci-ln4f.dts

···
 	};
 };
 
+&fiu {
+	status = "okay";
+
+	flash@0 {
+		reg = <0>;
+		compatible = "jedec,spi-nor";
+	};
+};
+
 &gpio0 {
 	gpio-line-names =
 		/* 0 */ "", "host-reset-control-n", "", "", "", "", "", "",