disp: msm: sde: clean up LTM driver states when lastclose is called

Clean up LTM buffers and reset LTM related lists when lastclose is
call to make sure LTM will be in clean state when hwc restarts or
when user runs LTM driver lua tests.

Change-Id: Ib2af68e70f2e5ff246aca890487085bc46dca7da
Signed-off-by: Ping Li <pingli@codeaurora.org>