arm64: dts: imx8mn-ddr4-evk: Add secondary cpus supply

Each cpu-core is supposed to list its supply separately, add
supply for secondary cpus.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts

@@ -17,6 +17,18 @@ &A53_0 {
 	cpu-supply = <&buck2_reg>;
 };
 
+&A53_1 {
+	cpu-supply = <&buck2_reg>;
+};
+
+&A53_2 {
+	cpu-supply = <&buck2_reg>;
+};
+
+&A53_3 {
+	cpu-supply = <&buck2_reg>;
+};
+
 &ddrc {
 	operating-points-v2 = <&ddrc_opp_table>;