This patch solves the following error:
arch/arm/boot/dts/rk3228-evb.dtb: ERROR (phandle_references): Reference to non-existent node or label "phy0"
Fixess 
db40f15b53e4 ("ARM: dts: rk3228-evb: Enable the integrated PHY for gmac")
Signed-off-by: David Wu <david.wu@rock-chips.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
        clock_in_out = "output";
        phy-supply = <&vcc_phy>;
        phy-mode = "rmii";
-       phy-handle = <&phy0>;
+       phy-handle = <&phy>;
        status = "okay";
 
        mdio {
                #address-cells = <1>;
                #size-cells = <0>;
 
-               phy@0 {
+               phy: phy@0 {
                        compatible = "ethernet-phy-id1234.d400", "ethernet-phy-ieee802.3-c22";
                        reg = <0>;
                        clocks = <&cru SCLK_MAC_PHY>;