Revert "drm: msm: sde: ensure all clients on primary vsyncs are unblocked"

This reverts commit 11a43274.
Change no longer needed on 4.19.

Change-Id: I02e5741e7a37aad8245665c85531d181cd1e6b08
Signed-off-by: Samantha Tran <samtran@codeaurora.org>