audioflinger: Avoid deadlock for sound recording - LPA concurrency.

-Rapid button press will cause next clip playback. If next clip is lpa
 clip, opening lpa clip triggers set parameter. The set parameter would
 acquire flinger lock and wait for completion. The wait can only be
 signalled from checkForNewParameters_l() in threadloop but the record
 thread loop will be blocked on processConfigEvents() on audio flinger
 lock resulting in deadlock and record failure.
-Release the lock before setParameter on threadbase is called to avoid
 the deadlock scenario.

Change-Id: Ib165210d16bcf661b6aa56aac1529375087e4e4e
CRs-Fixed: 390918