ARM: shmobile: kzm9g-reference dts: Add ak8975 magnetometer node

Add a DT node for the AK8975 magnetometer sensor, which is connected to
i2c0.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Specify the device interrupt to avoid polling for end of conversion.

While at it rename the DT node to compass@c to describe the device's
function instead of its model.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/sh73a0-kzm9g-reference.dts

@@ -189,6 +189,13 @@ &extal2_clk {
 &i2c0 {
 	status = "okay";
 
+	compass@c {
+		compatible = "asahi-kasei,ak8975";
+		reg = <0x0c>;
+		interrupt-parent = <&irqpin3>;
+		interrupts = <4 IRQ_TYPE_EDGE_FALLING>;
+	};
+
 	ak4648: codec@12 {
 		compatible = "asahi-kasei,ak4648";
 		reg = <0x12>;