disp: msm: sde: fix cwb, dp and wb tear down sequence

CWB, DP and WB displays tear down sequence must reset
3d_merge, ctl, pingpong_binding, etc. MDP HW
blocks. This change fixes the tear down
sequence register programming. It also moves flush
sw reset before encoder_disable call. That allows
CWB tear down to update the flush configuration
on primary ctl path.

Change-Id: I21c521b39456af4144cf836c65d46a25c985f51d
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>