target: msm8996: unstage display pipe when early animation stops

As in kernel, its handoff mechanism ensures no glitch will happen
during the handoff, so no need to stage display hardware pipe
when handoff starts in lk. Otherwise, some display will have
short stuck problem, which brings bad user experience.

Change-Id: I51101d7130ad66a6bf3e39ff02d47e390a85278e
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>