livedisplay: Fix another transition issue

 * If the screen is off during the entire transition period,
   when we turn the display back on it is not updated with
   the correct color temperature.
 * The code here is trying to be Mr. Smarty Pants and avoid
   extra updates, but it's totally pointless and also broken.
   There's no ill effects from writing to the hardware when
   the screen comes on, and updateColorTemperature already
   has all the other conditionals we need.
 * Just call updateColorTemperature every time, regardless.
   The LiveDisplayService ensures the callbacks run on the
   handler thread and all this crap can be removed.

Change-Id: Ib9560e13870a5c6bbe9c5a26fad40f5ec1cefa83