ARM: dts: omap4-droid4: Add LCD backlight

The TI LMU driver has not yet been merged, but the device
tree binding for TI LMU drivers has been acked already
earlier by Rob Herring <robh+dt@kernel.org>. So it should
be safe to apply to cut down the number of pending patches.

Cc: devicetree@vger.kernel.org
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Acked-by: Milo Kim <milo.kim@ti.com>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/omap4-droid4-xt894.dts

@@ -180,6 +180,25 @@ wlcore: wlcore@2 {
 	};
 };
 
+&i2c1 {
+	lm3532@38 {
+		compatible = "ti,lm3532";
+		reg = <0x38>;
+
+		enable-gpios = <&gpio6 12 GPIO_ACTIVE_HIGH>;
+
+		backlight {
+			compatible = "ti,lm3532-backlight";
+
+			lcd {
+				led-sources = <0 1 2>;
+				ramp-up-msec = <1>;
+				ramp-down-msec = <0>;
+			};
+		};
+	};
+};
+
 /*
  * REVISIT: Add gpio173 reset pin handling to the driver, see gpio-hog above.
  * If the GPIO reset is used, we probably need to have /lib/firmware/maxtouch.fw