arm64: dts: imx8mp-phycore-som: Remove invalid PMIC property

'regulator-compatible' is not a valid property according to
nxp,pca9450-regulator.yaml and causes the following warning:

  DTC_CHK arch/arm64/boot/dts/freescale/imx8mp-dhcom-pdk2.dtb
...
pmic@25: regulators:LDO1: Unevaluated properties are not allowed ('regulator-compatible' was unexpected)

Remove the invalid 'regulator-compatible' property.

Cc: Teresa Remmet <t.remmet@phytec.de>
Fixes: 88f7f6bc ("arm64: dts: freescale: Add support for phyBOARD-Pollux-i.MX8MP")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Teresa Remmet <t.remmet@phytec.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-phycore-som.dtsi

@@ -99,7 +99,6 @@ pmic: pmic@25 {
 
 		regulators {
 			buck1: BUCK1 {
-				regulator-compatible = "BUCK1";
 				regulator-min-microvolt = <600000>;
 				regulator-max-microvolt = <2187500>;
 				regulator-boot-on;
@@ -108,7 +107,6 @@ buck1: BUCK1 {
 			};
 
 			buck2: BUCK2 {
-				regulator-compatible = "BUCK2";
 				regulator-min-microvolt = <600000>;
 				regulator-max-microvolt = <2187500>;
 				regulator-boot-on;
@@ -119,7 +117,6 @@ buck2: BUCK2 {
 			};
 
 			buck4: BUCK4 {
-				regulator-compatible = "BUCK4";
 				regulator-min-microvolt = <600000>;
 				regulator-max-microvolt = <3400000>;
 				regulator-boot-on;
@@ -127,7 +124,6 @@ buck4: BUCK4 {
 			};
 
 			buck5: BUCK5 {
-				regulator-compatible = "BUCK5";
 				regulator-min-microvolt = <600000>;
 				regulator-max-microvolt = <3400000>;
 				regulator-boot-on;
@@ -135,7 +131,6 @@ buck5: BUCK5 {
 			};
 
 			buck6: BUCK6 {
-				regulator-compatible = "BUCK6";
 				regulator-min-microvolt = <600000>;
 				regulator-max-microvolt = <3400000>;
 				regulator-boot-on;
@@ -143,7 +138,6 @@ buck6: BUCK6 {
 			};
 
 			ldo1: LDO1 {
-				regulator-compatible = "LDO1";
 				regulator-min-microvolt = <1600000>;
 				regulator-max-microvolt = <3300000>;
 				regulator-boot-on;
@@ -151,7 +145,6 @@ ldo1: LDO1 {
 			};
 
 			ldo2: LDO2 {
-				regulator-compatible = "LDO2";
 				regulator-min-microvolt = <800000>;
 				regulator-max-microvolt = <1150000>;
 				regulator-boot-on;
@@ -159,7 +152,6 @@ ldo2: LDO2 {
 			};
 
 			ldo3: LDO3 {
-				regulator-compatible = "LDO3";
 				regulator-min-microvolt = <800000>;
 				regulator-max-microvolt = <3300000>;
 				regulator-boot-on;
@@ -167,13 +159,11 @@ ldo3: LDO3 {
 			};
 
 			ldo4: LDO4 {
-				regulator-compatible = "LDO4";
 				regulator-min-microvolt = <800000>;
 				regulator-max-microvolt = <3300000>;
 			};
 
 			ldo5: LDO5 {
-				regulator-compatible = "LDO5";
 				regulator-min-microvolt = <1800000>;
 				regulator-max-microvolt = <3300000>;
 				regulator-boot-on;