Add import of android.provider.Settings

One use case for changing settings during initialization is enabling airplane mode in safe mode bootup.

Test: manual
Change-Id: I846f09faca22b35f502a18348b70800d1edabb60

services/java/com/android/server/SystemServer.java

@@ -56,6 +56,7 @@ import android.os.SystemProperties;
 import android.os.Trace;
 import android.os.UserHandle;
 import android.os.storage.IStorageManager;
+import android.provider.Settings;
 import android.sysprop.VoldProperties;
 import android.util.DisplayMetrics;
 import android.util.EventLog;