ARM: tegra: colibri_t20: iris: add colibri ssp support

Add Colibri SSP aka SPI support using the SPI4 instance.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-colibri-iris.dts

@@ -164,6 +164,12 @@ usb-phy@c5008000 {
 		vbus-supply = <&reg_usbh_vbus>;
 	};
 
+	/* SPI4: Colibri SSP */
+	spi@7000da00 {
+		status = "okay";
+		spi-max-frequency = <25000000>;
+	};
+
 	/* SD/MMC */
 	sdhci@c8000600 {
 		status = "okay";