disp: msm: sde: wait for ctl to be idle to ensure transfer complete

With posted start, transfer complete cannot be guaranteed from
esd thread context if pending kickoff count is 1. While the
wait is going on, another commit can come and increment the
kickoff count. This can lead to scenarios where we wait for
pending kickoff count to be 0 during the wait period, which
can never happen if continuous commits are coming when
posted start is enabled. Add support to wait for ctl
to be idle to ensure frame transfer complete.

Change-Id: I3f6ac9fbef4087e08fd0b5c48bb691138c6bac12
Signed-off-by: Krishna Manikandan <mkrishn@codeaurora.org>