Revert "AudioPolicyService: Acquire mutex for SoundTriggerSession"

This reverts commit 5c74ff5045c976235767fcd62d87b2fc7023ff97.
diff --git a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
index a41ed95..a75e3dd 100644
--- a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
+++ b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
@@ -665,7 +665,6 @@
                                        audio_io_handle_t *ioHandle,
                                        audio_devices_t *device)
 {
-    Mutex::Autolock _l(mLock);
     if (mAudioPolicyManager == NULL) {
         return NO_INIT;
     }
@@ -675,7 +674,6 @@
 
 status_t AudioPolicyService::releaseSoundTriggerSession(audio_session_t session)
 {
-    Mutex::Autolock _l(mLock);
     if (mAudioPolicyManager == NULL) {
         return NO_INIT;
     }