arm64: dts: imx8mn-beacon-som: Assign PMIC clock

The PMIC throws an errors because the clock isn't assigned to it.
Fix this by assigning the clocks info.
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

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

@@ -120,6 +120,9 @@ pmic@4b {
 		interrupt-parent = <&gpio1>;
 		interrupts = <3 IRQ_TYPE_LEVEL_LOW>;
 		rohm,reset-snvs-powered;
+		#clock-cells = <0>;
+		clocks = <&osc_32k 0>;
+		clock-output-names = "clk-32k-out";
 
 		regulators {
 			buck1_reg: BUCK1 {