Add missing drawable for hdpi devices
Without this graphic, targets can't be added to the lockscreen.
E/AndroidRuntime(19136): Caused by:
android.content.res.Resources$NotFoundException: Resource ID #0x0
E/AndroidRuntime(19136):        at
android.content.res.Resources.getValue(Resources.java:1123)
E/AndroidRuntime(19136):        at
android.content.res.Resources.getDrawable(Resources.java:698)
E/AndroidRuntime(19136):        at
com.android.settings.slim.LockscreenTargets.initializeView(LockscreenTargets.java:187)
E/AndroidRuntime(19136):        at
com.android.settings.slim.LockscreenTargets.onActivityCreated(LockscreenTargets.java:147)

Change-Id: I0593506657b88443cc744314531c6a49023eac25