arm64: dts: imx8mn-evk: Add cpu-supply to enable cpufreq

PMIC driver is ready on i.MX8MN EVK board, assign cpu-supply for
each A53 and restore the operating points table to enable cpufreq.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

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

@@ -14,6 +14,22 @@ / {
 	compatible = "fsl,imx8mn-evk", "fsl,imx8mn";
 };
 
+&A53_0 {
+	cpu-supply = <&buck2>;
+};
+
+&A53_1 {
+	cpu-supply = <&buck2>;
+};
+
+&A53_2 {
+	cpu-supply = <&buck2>;
+};
+
+&A53_3 {
+	cpu-supply = <&buck2>;
+};
+
 &i2c1 {
 	pmic: pmic@25 {
 		compatible = "nxp,pca9450b";
@@ -109,19 +125,3 @@ ldo5: LDO5 {
 		};
 	};
 };
-
-&A53_0 {
-	/delete-property/operating-points-v2;
-};
-
-&A53_1 {
-	/delete-property/operating-points-v2;
-};
-
-&A53_2 {
-	/delete-property/operating-points-v2;
-};
-
-&A53_3 {
-	/delete-property/operating-points-v2;
-};