clearfog: Fix IRQ type of MAX14830

See my patches to linux-serial for details why this was broken.

Change-Id: Ied0412d80b33dace64cafb7bdd543174fa82c655
diff --git a/board/czechlight/clearfog/czechlight-clearfog.dts b/board/czechlight/clearfog/czechlight-clearfog.dts
index 83fb83b..028b2e7 100644
--- a/board/czechlight/clearfog/czechlight-clearfog.dts
+++ b/board/czechlight/clearfog/czechlight-clearfog.dts
@@ -46,7 +46,7 @@
 		clocks = <&spi_uart_clk>;
 		clock-names = "xtal";
 		interrupt-parent = <&gpio0>;
-		interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
+		interrupts = <25 IRQ_TYPE_LEVEL_LOW>;
 		pinctrl-0 = <&hack_pins>;
 		pinctrl-names = "default";
 		gpio-controller;