ARM: dts: omap4-sdp: Add support for pwm-backlight

Section to describe the backlight for the LCD panels.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NBenoit Cousson <benoit.cousson@linaro.org>

arch/arm/boot/dts/omap4-sdp.dts

@@ -95,6 +95,17 @@
 		};
 	};
 
+	backlight {
+		compatible = "pwm-backlight";
+		pwms = <&twl_pwm 1 7812500>;
+		brightness-levels = <
+				0 10 20 30 40
+				50 60 70 80 90
+				100 110 120 127
+				>;
+		default-brightness-level = <13>;
+	};
+
 	sound {
 		compatible = "ti,abe-twl6040";
 		ti,model = "SDP4430";