Rotator getting stuck leading to fence timeout

Even though cancel_delayed_work should cancel the worker thread
in some race condition it can fail and get scheduled.
To avoid this situation use cancel_delayed_work_sync.
Also rotator_lock mutex need not be unlocked while waiting for isr
as isr does not aquire this mutex for doing its operations.
It is after this unlock of mutex sometimes in race condition rotator
clock is getting disabled via the msm_rotator_rot_clk_work_f

Conflicts:
	drivers/char/msm_rotator.c

Change-Id: I5405f2c4d9505c1b288d1f1ac3d9892955306f87

Signed-off-by: Justin Philip <jphili@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>