dt-bindings: power: supply: max17040: Add maxim,rcomp

To compensate for the battery chemistry and operating conditions the
chips support a compensation value. Specify one or two byte compensation
via the maxim,rcomp byte array.
Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/max17040_battery.txt

@@ -17,6 +17,11 @@ Optional properties :
 				Specify this boolean property to divide the
 				reported value in 2 and thus normalize it.
 				SOC == State of Charge == Capacity.
+- maxim,rcomp :			A value to compensate readings for various
+				battery chemistries and operating temperatures.
+				max17040,41 have 2 byte rcomp, default to
+				0x97 0x00. All other devices have one byte
+				rcomp, default to 0x97.
 - interrupts : 			Interrupt line see Documentation/devicetree/
 				bindings/interrupt-controller/interrupts.txt
 - wakeup-source :		This device has wakeup capabilities. Use this
@@ -41,6 +46,7 @@ Example:
 	battery-fuel-gauge@36 {
 		compatible = "maxim,max17048";
 		reg = <0x36>;
+		maxim,rcomp = /bits/ 8 <0x56>;
 		maxim,alert-low-soc-level = <10>;
 		maxim,double-soc;
 	};