arm: dts: rockchip: px30: add and enable rng node

Add enable rng node in px30-evb-u-boot.dtsi.

Signed-off-by: Lin Jinhan <troy.lin@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/px30-evb-u-boot.dtsi b/arch/arm/dts/px30-evb-u-boot.dtsi
index aea9f4d..61b1433 100644
--- a/arch/arm/dts/px30-evb-u-boot.dtsi
+++ b/arch/arm/dts/px30-evb-u-boot.dtsi
@@ -4,3 +4,7 @@
  */
 
 #include "px30-u-boot.dtsi"
+
+&rng {
+	status = "okay";
+};