Add HAL interface to replace aaudio system property.

Using the HAL interface instead of reading system property is a better
option when moving to AIDL HAL. The replaced property includes:
  - aaudio.mixer_bursts
  - aaudio.hw_burst_min_usec

Test: atest AAudioTests
Bug: 193275465
Change-Id: I9c9a04296e56ff083babcfa089fcdddc6b89ed94
diff --git a/media/libaudiohal/impl/DeviceHalHidl.h b/media/libaudiohal/impl/DeviceHalHidl.h
index 6065b40..9fd0ac0 100644
--- a/media/libaudiohal/impl/DeviceHalHidl.h
+++ b/media/libaudiohal/impl/DeviceHalHidl.h
@@ -126,6 +126,16 @@
         return INVALID_OPERATION;
     }
 
+    int32_t getAAudioMixerBurstCount() override {
+        // TODO: Implement the HAL query when moving to AIDL HAL.
+        return INVALID_OPERATION;
+    }
+
+    int32_t getAAudioHardwareBurstMinUsec() override {
+        // TODO: Implement the HAL query when moving to AIDL HAL.
+        return INVALID_OPERATION;
+    }
+
     status_t dump(int fd, const Vector<String16>& args) override;
 
   private: