msm: rotator: non-blocking rotate

Send request to a work queue and return right away.
Work queue will go through the commit queue to do the
rotation. wait_for_finish can be set to true to make
rotation go back to blocking.

Change-Id: I35791dd5f7eb0a865e9dd0641ba0cfd335db8850
Signed-off-by: Ken Zhang <kenz@codeaurora.org>

Conflicts:

	drivers/char/msm_rotator.c