[U-Boot] OF_PLATDATA questions on rk3399 platfrom

[Ziyuan <xzy.xu@rock-chips.com>]

hi simon,

I need to achieve emmc_phy physical address in driver, so that I can 
configure phy in different scenarios (phy register address should be 
0xff77f780). see below:
     sdhci: sdhci at fe330000 {

         phys = <&emmc_phy>;
         phy-names = "phy_arasan";

     };

     grf: syscon at ff770000 {
         reg = <0x0 0xff770000 0x0 0x10000>;

         emmc_phy: phy at f780 {
             compatible = "rockchip,rk3399-emmc-phy";
             reg = <0xf780 0x24>;
             #phy-cells = <0>;
             status = "disabled";
         };
     };

  AKA, I can't use libfdt if OF_PLATDATA is enabled,  so how to get it?