ARM: tegra: device tree whitespace cleanup

Remove white-space from empty line; triggers checkpatch.
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/boot/dts/tegra20.dtsi

@@ -209,7 +209,7 @@ das {
 		compatible = "nvidia,tegra20-das";
 		reg = <0x70000c00 0x80>;
 	};
-	
+
 	tegra_ac97: ac97 {
 		compatible = "nvidia,tegra20-ac97";
 		reg = <0x70002000 0x200>;