ARM: shmobile: r8a7794: alt: Fix ethernet controller PHY IRQ line

The PHY IRQ line is connected to external IRQ8, not IRQ0. Fix DT
accordingly.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7794-alt.dts

@@ -51,7 +51,7 @@ &ether {
 	phy1: ethernet-phy@1 {
 		reg = <1>;
 		interrupt-parent = <&irqc0>;
-		interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
+		interrupts = <8 IRQ_TYPE_LEVEL_LOW>;
 		micrel,led-mode = <1>;
 	};
 };