msm: mdss: remove cleanup done during overlay kickoff

Remove kickoff done from overlay kickoff, this was done to clear
potentially stale handles when the process using it has crashed. However
this case is handled in commit a3b3d215 by handling per process
resources.

Change-Id: I9c060b107c004c6cfb726ad84ae69d77461ed74f
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>