arm64: dts: ti: k3-j721e-mcu: add scm node and phy-gmii-sel nodes

Add DT node for MCU System Control module DT node and DT node for the TI
J721E SoC phy-gmii-sel PHY required for Ethernet ports mode selection.
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

arch/arm64/boot/dts/ti/k3-j721e-mcu-wakeup.dtsi

@@ -34,6 +34,20 @@ k3_reset: reset-controller {
 		};
 	};
 
+	mcu_conf: syscon@40f00000 {
+		compatible = "syscon", "simple-mfd";
+		reg = <0x0 0x40f00000 0x0 0x20000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x0 0x0 0x40f00000 0x20000>;
+
+		phy_gmii_sel: phy@4040 {
+			compatible = "ti,am654-phy-gmii-sel";
+			reg = <0x4040 0x4>;
+			#phy-cells = <1>;
+		};
+	};
+
 	wkup_pmx0: pinmux@4301c000 {
 		compatible = "pinctrl-single";
 		/* Proxy 0 addressing */