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: Ifc2e36bd24d9681d42105f4ccbb62a8777af2a6c
Signed-off-by: Ken Zhang <kenz@codeaurora.org>