soundtrigger: remove warning from VTS test

Test: pass
Change-Id: I5b437980fb8003cbfb56b0ab9079993565224fa6
diff --git a/soundtrigger/2.0/vts/functional/VtsHalSoundtriggerV2_0TargetTest.cpp b/soundtrigger/2.0/vts/functional/VtsHalSoundtriggerV2_0TargetTest.cpp
index 273ee14..fcc989f 100644
--- a/soundtrigger/2.0/vts/functional/VtsHalSoundtriggerV2_0TargetTest.cpp
+++ b/soundtrigger/2.0/vts/functional/VtsHalSoundtriggerV2_0TargetTest.cpp
@@ -310,7 +310,6 @@
  */
 TEST_F(SoundTriggerHidlTest, stopAllRecognitions) {
     Return<int32_t> hidlReturn(0);
-    SoundModelHandle handle = 0;
 
     hidlReturn = mSoundTriggerHal->stopAllRecognitions();