ARM: dts: wpcm450: Add FIU SPI controller node

Add the SPI controller (FIU, Flash Interface Unit) to the WPCM450
devicetree, according to the newly defined binding, as well as the SHM
(shared memory interface) syscon.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20221105185911.1547847-6-j.neuschaefer@gmx.netSigned-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/nuvoton-wpcm450.dtsi

@@ -456,5 +456,21 @@ hg7_pins: mux-hg7 {
 				function = "hg7";
 			};
 		};
+
+		fiu: spi-controller@c8000000 {
+			compatible = "nuvoton,wpcm450-fiu";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <0xc8000000 0x1000>, <0xc0000000 0x4000000>;
+			reg-names = "control", "memory";
+			clocks = <&clk 0>;
+			status = "disabled";
+		};
+
+		shm: syscon@c8001000 {
+			compatible = "nuvoton,wpcm450-shm", "syscon";
+			reg = <0xc8001000 0x1000>;
+			reg-io-width = <1>;
+		};
 	};
 };