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

This change adds the required functions in the include directory
that will check if any secondary clients are waiting on vsync
wait_queue and unblock them during primary vsync disable.

Change-Id: I1cc146dbf6dc31ac3037b8ddaa5492655a2ac14c
Signed-off-by: Samantha Tran <samtran@codeaurora.org>