ARM: tegra: Add head numbers to display controllers

The number of the head specifies the index of the display controller
unit and is required to properly configure outputs so that they receive
video data from the correct source.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
index 480ecda..48d2a7f 100644
--- a/arch/arm/boot/dts/tegra20.dtsi
+++ b/arch/arm/boot/dts/tegra20.dtsi
@@ -94,6 +94,8 @@
 			resets = <&tegra_car 27>;
 			reset-names = "dc";
 
+			nvidia,head = <0>;
+
 			rgb {
 				status = "disabled";
 			};
@@ -109,6 +111,8 @@
 			resets = <&tegra_car 26>;
 			reset-names = "dc";
 
+			nvidia,head = <1>;
+
 			rgb {
 				status = "disabled";
 			};