ARM: tegra: Provide specific compatible string for Nexus 7 panel

panel-lvds alone is not a valid compatible string and we always need a
specific compatible string as well. Nexus 7 can come with one of (at
least) two panels, so pick one of them as the specific compatible
string.
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-common.dtsi

@@ -1092,15 +1092,11 @@ cpu3: cpu@3 {
 
 	display-panel {
 		/*
-		 * Nexus 7 supports two compatible panel models:
-		 *
-		 *  1. hydis,hv070wx2-1e0
-		 *  2. chunghwa,claa070wp03xg
-		 *
-		 * We want to use timing which is optimized for Nexus 7,
-		 * hence we need to customize the timing.
+		 * Some device variants come with a Hydis HV070WX2-1E0, but
+		 * since they are all largely compatible, we'll go with the
+		 * Chunghwa one here.
 		 */
-		compatible = "panel-lvds";
+		compatible = "chunghwa,claa070wp03xg", "panel-lvds";
 
 		width-mm = <94>;
 		height-mm = <150>;