audioflinger: Fix to release wakelock after closeoutput

-In DirectTrack destructor, closeOutput is called after
releaseWakelock is done. This may sometimes result in
power collapse happening even before actual close
sequence of Audio path is completed and will result
in high power consumption.
-Release wakelock only after closeOutput is done
in directtrack destructor.

CRs-fixed: 438179
Change-Id: Ibe103804daf2cb09bade998d6d34c3a34508dd09