rockchip: px5: add timer0 dts node as tick timer

Let's use rockchip timer before stimer patches can be merged.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

arch/arm/dts/rk3368-px5-evb-u-boot.dtsi

@@ -5,6 +5,7 @@
 / {
 	chosen {
 		u-boot,spl-boot-order = &emmc;
+		tick-timer = "/timer@ff810000";
 	};
 };
 
@@ -60,3 +61,9 @@
 &emmc {
 	u-boot,dm-pre-reloc;
 };
+
+&timer0 {
+	u-boot,dm-pre-reloc;
+	clock-frequency = <24000000>;
+	status = "okay";
+};