hwc: Sync for rotator

Implement sync for rotator.
If a buffer is rotated, it can be used by producer soon after
rotation (and it wont have to wait until vsync).

Mdp waits for the rotator buffer's release fence to signal
to start display.

Hwc waits for previous access to rotator buffer by MDP to finish
before using it

Change-Id: I5664806a17c44d58af62a2825ce454089fcd31cf
7 files changed