ARM: shmobile: marzen-reference: Use falling edge IRQ for LAN9221

The device is configured to generate an active-low interrupt signal that
is automatically deasserted without requiring any action from the host.
Use falling edge trigger as that is the configuration currently used on
the board.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7779-marzen-reference.dts

@@ -44,7 +44,7 @@
 
 		phy-mode = "mii";
 		interrupt-parent = <&irqpin0>;
-		interrupts = <1 IRQ_TYPE_NONE>; /* IRQ1: hwirq 1 on irqpin0 */
+		interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
 		reg-io-width = <4>;
 		vddvario-supply = <&fixedregulator3v3>;
 		vdd33a-supply = <&fixedregulator3v3>;