Revert "drm: msm: sde: remove user commit validity check"

This reverts commit b80fa288.

This change can't guarante the sequence of smmu operation for
early splash case, and more, the commit validity check is
mandatory to avoid potential glitch during display handoff.
So revert this change.

Change-Id: Ic8327dedc1357ed5d8ef6ca490390ce66b7eb986
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>