ARM: dts: exynos: correct PMIC interrupt trigger level on Arndale Octa

The Samsung PMIC datasheets describe the interrupt line as active low
with a requirement of acknowledge from the CPU.  The falling edge
interrupt will mostly work but it's not correct.

Fixes: 1fed225271 ("ARM: dts: fix pinctrl for s2mps11-irq on exynos5420-arndale-octa")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20201210212903.216728-5-krzk@kernel.org

arch/arm/boot/dts/exynos5420-arndale-octa.dts

@@ -349,7 +349,7 @@
 		reg = <0x66>;
 
 		interrupt-parent = <&gpx3>;
-		interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
+		interrupts = <2 IRQ_TYPE_LEVEL_LOW>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&s2mps11_irq>;