msm: rotator: sync point support

Add MSM_ROTATOR_IOCTL_BUFFER_SYNC ioctl interface.
Rotator will create a timeline for each session at START, wait for
input fence and create released fence in this ioctl call,
signal the timeline after rotation is done.

Change-Id: I3738f8287d804ccd94e0a16ac0afb8b41b299c75
Signed-off-by: Ken Zhang <kenz@codeaurora.org>

Conflicts:
	drivers/char/msm_rotator.c