arm64: dts: imx8mn: Add LDO5 regulator-name to Variscite VAR-SOM-MX8MN

The PMIC on this Variscite SOM and its MX8MM variant lists regulator-name
for all LDOs except this LDO5, add the regulator-name property to avoid
this omission.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi

@@ -207,6 +207,7 @@ ldo4_reg: LDO4 {
 			};
 
 			ldo5_reg: LDO5 {
+				regulator-name = "ldo5";
 				regulator-min-microvolt = <1800000>;
 				regulator-max-microvolt = <1800000>;
 				regulator-always-on;