boards: qemu_cortex_a9: add MDIO and PHY

enable MDIO in the board's Kconfig, specify the Ethernet operational
mode for QEMU, add/configure MDIO/PHY nodes in the device tree.

Signed-off-by: Immo Birnbaum <mail@birnbaum.immo>

Author: ibirnbaum

boards/qemu/cortex_a9/Kconfig.defconfig

@@ -29,6 +29,9 @@ if NETWORKING
 config NET_L2_ETHERNET
 	default y
 
+config MDIO
+	default y
+
 config NET_TX_STACK_SIZE
 	default 8192
 

boards/qemu/cortex_a9/qemu_cortex_a9.dts

@@ -57,7 +57,17 @@
 
 &gem0 {
 	status = "okay";
+	phy-handle = <&gem0_phy>;
 	clock-frequency = <1000000000>;
-	mdc-divider = <XLNX_GEM_MDC_DIVIDER_224>;
 	local-mac-address = [00 00 00 01 02 03];
 };
+
+&gem0_mdio {
+	status = "okay";
+
+	gem0_phy: phy@1 {
+		compatible = "marvell,88e1xxx";
+		reg = <1>;
+		status = "okay";
+	};
+};