arm64: dts: renesas: r8a77990: ebisu: Add GPIO expander

Describe the ON Semiconductor PCA9654 I/O expander on the first I2C
bus, which provides 8 extra GPIOs.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts

@@ -337,6 +337,15 @@ &hsusb {
 &i2c0 {
 	status = "okay";
 
+	io_expander: gpio@20 {
+		compatible = "onnn,pca9654";
+		reg = <0x20>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		interrupt-parent = <&gpio2>;
+		interrupts = <22 IRQ_TYPE_LEVEL_LOW>;
+	};
+
 	hdmi-encoder@39 {
 		compatible = "adi,adv7511w";
 		reg = <0x39>;