msm: mdss: rotator: fix synchronization issue with multiple sessions

Current rotator driver allows more sessions than actual number of rotator
hardware. This requires virtualization when number of active sessions are
greater than number of rotators. In the current implementation,
synchronization bug is getting exposed if one rotator has two or more
sessions, all these sessions are actively using shared rotator in
interleave fashion and one of the session is using optimized path where
back to back configuration is same. This leads to unexpected results and
device hang. Fix this by maintaining proper ownership and hand-off when
one session is finished using given rotator and other one picks up.

Change-Id: I1f2e7376a01f248d11253bf5b6153ab236f07b19
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>