Bootani: refactor Legacy's bootanimation makefile

* add hdpi xhdpi xxhdpi bootanimation barriers

NOTE: all new devices or variants added, pls add
      to barrier under alphabetical order to satisfy
      Ricky's OCD & mine too :)

Signed-off-by: houst0nn <houstonn@gmail.com>

Change-Id: I7a4b7c1d7a60bd5b017fceb63dabd9cdfcc203c3