arm64: dts: rockchip: Enable SPI1 on Ficus

Enable SPI1 exposed on both Low and High speed expansion connectors
of Ficus. SPI1 has 3 different chip selects wired as below:

CS0 - Serial Flash (unpopulated)
CS1 - Low Speed expansion
CS2 - High Speed expansion
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-ficus.dts

@@ -146,6 +146,12 @@ bt_led: bt_led {
 	};
 };
 
+&spi1 {
+	/* On both Low speed and High speed expansion */
+	cs-gpios = <0>, <&gpio4 RK_PA6 0>, <&gpio4 RK_PA7 0>;
+	status = "okay";
+};
+
 &usbdrd_dwc3_0 {
 	dr_mode = "host";
 };