arm64: dts: imx8mm-beacon-som: fix missing PMIC's interrupt line pull-up

The PMIC's interrupt is level low and should be pulled up.  The PMIC's
device node had pinctrl-0 property but it lacked pinctrl-names which
is required to apply the pin configuration.

Fixes: 5f67317b ("arm64: dts: imx8mm: correct interrupt flags")
Fixes: 593816fa ("arm64: dts: imx: Add Beacon i.MX8m-Mini development kit")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-beacon-som.dtsi

@@ -72,6 +72,7 @@ &i2c1 {
 	pmic@4b {
 		compatible = "rohm,bd71847";
 		reg = <0x4b>;
+		pinctrl-names = "default";
 		pinctrl-0 = <&pinctrl_pmic>;
 		interrupt-parent = <&gpio1>;
 		interrupts = <3 IRQ_TYPE_LEVEL_LOW>;