audio: fix for deadlock issue during LPA playback

EffectModule::setEnable for LPA playback was modified to lock
AudioFligner::mLock with EffectModule::mLock held.
And at the same time ~DirectAudioTrack is trying to lock
EffectModule::mLock with AudioFlinger::mLock held and this
results in deadlock.
Fix this issue by reverting previous change and acquire
locks in certain sequence to avoid deadlock in setEnabled_l

Change-Id: Iea74eb3591a728275c655074a4d2017bd38f99ab