arm64: dts: imx8mq-librem5: add the magnetometer mount matrix

Userland needs the mount matrix to know the correct orientation of
the part.
Signed-off-by: Angus Ainslie <angus@akkea.ca>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dtsi

@@ -38,6 +38,12 @@ MX8MQ_IOMUXC_SPDIF_RX_GPIO5_IO4		0x83
 	};
 };
 
+&magnetometer {
+	mount-matrix =  "1",  "0",  "0",
+			"0", "-1",  "0",
+			"0",  "0", "-1";
+};
+
 &proximity {
 	proximity-near-level = <25>;
 };

arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi

@@ -981,7 +981,7 @@ &i2c2 {
 	pinctrl-0 = <&pinctrl_i2c2>;
 	status = "okay";
 
-	magnetometer@1e	{
+	magnetometer: magnetometer@1e	{
 		compatible = "st,lsm9ds1-magn";
 		reg = <0x1e>;
 		pinctrl-names = "default";