arm64: dts: librem5: add a battery for the bq25896 to monitor

Add a simple-battery with default power capacity

Discharge curve comes from the panasonic NCR18650B datasheet

https://www.batteryspace.com/prod-specs/NCR18650B.pdf

Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>

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

@@ -26,6 +26,22 @@
 		power-supply = <&reg_22v4_p>;
 	};
 
+	bat: battery {
+		compatible = "simple-battery";
+		voltage-min-design-microvolt = <3000000>;
+		voltage-max-design-microvolt = <4192000>;
+		energy-full-design-microwatt-hours = <11700000>;
+		charge-full-design-microamp-hours = <3250000>;
+		precharge-current-microamp = <130000>;
+		charge-term-current-microamp = <66000>;
+		constant-charge-current-max-microamp = <1600000>;
+		constant-charge-voltage-max-microvolt = <4200000>;
+		factory-internal-resistance-micro-ohms = <250000>;
+		ocv-capacity-celsius = <25>;
+		ocv-capacity-table-0 = <4192000 100>, <3750000 85>, <3650000 68>,
+			<3500000 51>, <3400000 34>, <3250000 17>, <3000000 0>;
+	};
+
 	chosen {
 		stdout-path = &uart1;
 	};
@@ -500,6 +516,7 @@
 		ti,boost-max-current = <50000>; /* 50mA */
 		ti,use-vinmin-threshold = <1>; /* enable VINDPM */
 		ti,vinmin-threshold = <3900000>; /* 3.9V */
+		monitored-battery = <&bat>;
 	};
 };