hwc/overlay: Video on 4k2k external, 4k2k rotation.

-Add support for Video via overlay on 4k2k external panel.
-Add support for rotating videos on 4k2k panels. We use
pre-rotation in hwc to rotate a video into a single buffer,
irrespective of panel size. Then this buffer is fed to MDP.
Rotator objects are managed by the new RotMgr.
-Cleaup mdpcomp and overlay.

Change-Id: Ifb08534747e8e18b6c58dd8a3e1a9947409100f1
22 files changed