disp: msm: sde: avoid tx wait during cwb disable and reset

TX wait during CWB encoder disable can cause a jank, as we
are not able to flush before next vsync due to delay in wait.
Changes are made to avoid TX wait during disable, separate and
delay reset encoder call till CWB frame done trigger, so that
there will be enough time to flush before next vsync.

Change-Id: Ib0e8561f4727523ec6520528beb855ae972e6909
Signed-off-by: Karthik Andhavarapu <kartkart@codeaurora.org>