drm/msm/sde: program color fill in planes in failure at commit stage

During secure transition, failure in _sde_plane_set_scanout at
atomic commit stage can lead to unsecure buffer address being
programmed to secure pipe and lead to stage 2 smmu faults.
These failure cases are taken care by inducing solid fill color
on such planes.

Change-Id: I3ba19b040b5a71b7d7f3629de650037f6027b656
Signed-off-by: Raviteja Tamatam <travitej@codeaurora.org>