ARM: shmobile: bockw-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.
Configure the IRQ to trigger on falling edge.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7778-bockw-reference.dts

@@ -46,7 +46,7 @@ ethernet@18300000 {
 
 		phy-mode = "mii";
 		interrupt-parent = <&irqpin>;
-		interrupts = <0 IRQ_TYPE_NONE>; /* IRQ0: hwirq 0 on irqpin */
+		interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
 		reg-io-width = <4>;
 		vddvario-supply = <&fixedregulator3v3>;
 		vdd33a-supply = <&fixedregulator3v3>;