Settings: Check if we have any color modes declared in overlay

* Checking for wide gamut support isn't always enough

Change-Id: Ic7257e37f2eca97450eaf0ca1e330de7596352be
diff --git a/src/com/android/settings/display/ColorModePreferenceController.java b/src/com/android/settings/display/ColorModePreferenceController.java
index 6cd4867..14a2241 100644
--- a/src/com/android/settings/display/ColorModePreferenceController.java
+++ b/src/com/android/settings/display/ColorModePreferenceController.java
@@ -28,8 +28,11 @@
 
     @Override
     public int getAvailabilityStatus() {
+        final int[] availableColorModes = mContext.getResources().getIntArray(
+                com.android.internal.R.array.config_availableColorModes);
         return mContext.getSystemService(ColorDisplayManager.class)
                 .isDeviceColorManaged()
+                && availableColorModes.length > 0
                 && !ColorDisplayManager.areAccessibilityTransformsEnabled(mContext) ?
                 AVAILABLE : DISABLED_FOR_USER;
     }