fix phy_interrupt issue on picoimx board

The MDIO interrupt should be triggered when activation type is low.

Change-Id: I42024b58c642805caf9dbd3679ae47f9504632df
Signed-off-by: fang hui <hui.fang@freescale.com>
diff --git a/arch/arm/boot/dts/imx6ul-picosom-hobbit.dts b/arch/arm/boot/dts/imx6ul-picosom-hobbit.dts
index 76179a4..42968dc 100644
--- a/arch/arm/boot/dts/imx6ul-picosom-hobbit.dts
+++ b/arch/arm/boot/dts/imx6ul-picosom-hobbit.dts
@@ -670,7 +670,7 @@
 			reg = <1>;
 			max-speed = <100>;
 			interrupt-parent = <&gpio5>;
-			interrupts = <6 IRQ_TYPE_LEVEL_HIGH 0>;
+			interrupts = <6 IRQ_TYPE_LEVEL_LOW 0>;
 		};
 	};
 };