msm: camera: sync: Change the sync state first

First thing to do when starting deinit should be to change the
state to INVALID. Many other places rely on this state to avoid
processing and hence avoid race.

Change-Id: I402b15573c5fb4229d6c006a32f55ab3608d476f
Signed-off-by: Harsh Shah <harshs@codeaurora.org>