hwc: 8084: Split videos with width > 2048 if source split absent

Split video with width > 2048 only if source split is absent, and
the relevant system property is set.
In source split the video is split evenly anyway.

Change-Id: Iab0af427756d32120a160787ecfb7c974dbbeea1
(cherry picked from commit c6f6ce9981e095965c7aec262954f5afbd24043a)