xilinx: Fix mdio bus description for vck190-sc

Current behavior is that eth_phy_get_mdio_bus

Net:   FEC: can't find phy-handle

ZYNQ GEM: ff0b0000, mdio bus ff0b0000, phyaddr 0, interface sgmii
eth0: ethernet@ff0b0000

Net:
ZYNQ GEM: ff0b0000, mdio bus ff0b0000, phyaddr 0, interface sgmii
eth0: ethernet@ff0b0000

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/5b7da5808136b3f579c0cf7a3431b56c758655e9.1662460749.git.michal.simek@amd.com
diff --git a/arch/arm/dts/zynqmp-e-a2197-00-revA.dts b/arch/arm/dts/zynqmp-e-a2197-00-revA.dts
index 4940825..3fa18f5 100644
--- a/arch/arm/dts/zynqmp-e-a2197-00-revA.dts
+++ b/arch/arm/dts/zynqmp-e-a2197-00-revA.dts
@@ -155,8 +155,12 @@
 	phy-handle = <&phy0>;
 	phy-mode = "sgmii";
 	is-internal-pcspma;
-	phy0: ethernet-phy@0 { /* u131 M88E1512 */
-		reg = <0>;
+	mdio: mdio {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		phy0: ethernet-phy@0 { /* u131 M88E1512 */
+			reg = <0>;
+		};
 	};
 };