arm64: dts: rockchip: add cpu-id nvmem cell node for rk3399

There is a 'cpu-id' field in efuse, export it for other drivers
reference.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399.dtsi

@@ -1023,6 +1023,9 @@
 		clock-names = "pclk_efuse";
 
 		/* Data cells */
+		cpu_id: cpu-id@7 {
+			reg = <0x07 0x10>;
+		};
 		cpub_leakage: cpu-leakage@17 {
 			reg = <0x17 0x1>;
 		};