rockchip: Pinebook Pro: enable rng to provide an entropy source

Enable the rng so UEFI can provide entropy for KASLR

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi b/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi
index 1a2e24d..296321d 100644
--- a/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi
+++ b/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi
@@ -24,6 +24,10 @@
 	u-boot,dm-pre-reloc;
 };
 
+&rng {
+	status = "okay";
+};
+
 &sdhci {
 	max-frequency = <25000000>;
 	u-boot,dm-pre-reloc;