Basic target VTS test for Sound Trigger HAL

As all sound trigger HAL implementations use proprietary
sound models this just tests proper enumeration of HAL
properties and proper error response from HAL when methods are called
with obviously wrong arguments or out of sequence.

Test: build and run test
Bug: 32022431
Change-Id: I6eca0dc100843141752665f7a0d4749fc7eda6fc
diff --git a/soundtrigger/Android.bp b/soundtrigger/Android.bp
index c12cd4f..8d2c986 100644
--- a/soundtrigger/Android.bp
+++ b/soundtrigger/Android.bp
@@ -1,4 +1,5 @@
 // This is an autogenerated file, do not edit.
 subdirs = [
     "2.0",
+    "2.0/vts/functional",
 ]