ARM: dts: twl4030: Add iio properties for bci subnode

Added new iio properties which are required for twl4030-charger driver and
allow to use twl4030-madc indirectly.
Signed-off-by: Marek Belisko <marek@goldelico.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

arch/arm/boot/dts/twl4030.dtsi

@@ -22,6 +22,8 @@ rtc {
 	charger: bci {
 		compatible = "ti,twl4030-bci";
 		interrupts = <9>, <2>;
+		io-channels = <&twl4030_madc 11>;
+		io-channel-name = "vac";
 		bci3v1-supply = <&vusb3v1>;
 	};