sdm: Reduce scope of lock in deinit

HWEventsInterface::Destroy tries to shutdown the event thread,
but it is not able to do so while holding the recursive mutex,
since there is a race where the idle power collapse event is also
received at the same time, which tries to acquire the recursive
mutex.

Fixes test Hwc2Test.SET_VSYNC_ENABLED*
Change-Id: I5dfe75b25606c19156ee12073dacda43541dd9cf
CRs-Fixed: 2028722
1 file changed