hal: spkr_prot: release adev lock during sleep

During speaker thermal calibration, read speaker temperature
5 times with one second sleep time with adev lock acquired.
If any playback starts during that time, it will wait for
adev lock till temperature reading is done. Unblock the
playback thread by release the adev lock during sleep.

Change-Id: I383248d9a701a98c776ca019b628adc22a145e60