arm64: dts: imx8mn-ddr4-evk: fix missing PMIC's interrupt line pull-up

arm64: dts: imx8mn-ddr4-evk: 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: 4153f7811a9b ("arm64: dts: imx8mn: correct interrupt flags")
Fixes: 3e44dd09736d ("arm64: dts: imx8mn-ddr4-evk: Add rohm,bd71847 PMIC support")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>