arm64: tegra: Add #power-domain-cells for BPMP

Add #power-domain-cells for the BPMP node on Tegra186 so that the power
domain provider may be used.
Signed-off-by: NMikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra186.dtsi

@@ -443,6 +443,7 @@
 		shmem = <&cpu_bpmp_tx &cpu_bpmp_rx>;
 		#clock-cells = <1>;
 		#reset-cells = <1>;
+		#power-domain-cells = <1>;
 
 		bpmp_i2c: i2c {
 			compatible = "nvidia,tegra186-bpmp-i2c";