disp: msm: sde: avoid wb done wait for cwb in wait_for_commit

Existing cwb implementation waits for WB done interrupt in
wait_for_commit_done API call. This serializes the cwb commit
and causes frame trigger delay on primary display. MDSS hw allows
to trigger the cwb frame when previous frame is in-progress. This
change updates driver to allow parallel frame trigger for cwb
enabled display. It releases frame N cwb output buffer in frame
N+1 wait_for_commit done call.

Change-Id: Id4f2a0cc78a3f24a1b5ce96dc907780246768dbf
Signed-off-by: Raviteja Tamatam <travitej@codeaurora.org>