arm64: tegra: Remove unused #power-domain-cells property

Remove the "#power-domain-cells" property which was incorrectly
included by commit e53095857166 ("arm64: tegra: Add Tegra210
support").
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra210.dtsi

@@ -580,8 +580,6 @@ pmc: pmc@7000e400 {
 		reg = <0x0 0x7000e400 0x0 0x400>;
 		clocks = <&tegra_car TEGRA210_CLK_PCLK>, <&clk32k_in>;
 		clock-names = "pclk", "clk32k_in";
-
-		#power-domain-cells = <1>;
 	};
 
 	fuse@7000f800 {