rockchip: rk3399: Move u-boot, dm-pre-reloc of uart0, uart2

u-boot,dm-pre-reloc for uart0, uart2 indeed u-boot specific
properties. Move them into rk3399-u-boot.dtsi so the boards
which enabled these node will available during SPL.
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>
Reviewed-by: NKever Yang <kever.yang@rock-chips.com>

arch/arm/dts/rk3399-gru.dtsi

@@ -629,7 +629,6 @@ ap_i2c_audio: &i2c8 {
 
 &uart2 {
 	status = "okay";
-	u-boot,dm-pre-reloc;
 };
 
 &usb_host0_ohci {

arch/arm/dts/rk3399-puma.dtsi

@@ -639,7 +639,6 @@
 };
 
 &uart0 {
-	u-boot,dm-pre-reloc;
 	pinctrl-names = "default";
 	pinctrl-0 = <&uart0_xfer &uart0_cts>;
 	status = "okay";

arch/arm/dts/rk3399-u-boot.dtsi

@@ -10,3 +10,11 @@
 &spi1 {
 	u-boot,dm-pre-reloc;
 };
+
+&uart0 {
+	u-boot,dm-pre-reloc;
+};
+
+&uart2 {
+	u-boot,dm-pre-reloc;
+};