liboverlay: Allocate cached rotator buffers

- gralloc does not invalidate and clean the cached buffers.
- Using cached buffers for rotator does not add any benefit as
  rotator doesn't touch the L2 cache. Since no one accesses the
  memory but the rotator and mdp, so make rotator buffers uncached

Change-Id: I3dc3c91afb2fc07b7473662323339aac1cea3d73
1 file changed