Use -Werror in hardware/interfaces/audio

* Remove unused variables, lambda function parameters..

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I28e8eb1af434f62cab6f41285b9a400f7f57cd13
diff --git a/audio/2.0/default/Android.mk b/audio/2.0/default/Android.mk
index 621853c..70fa750 100644
--- a/audio/2.0/default/Android.mk
+++ b/audio/2.0/default/Android.mk
@@ -30,6 +30,8 @@
     StreamIn.cpp \
     StreamOut.cpp \
 
+LOCAL_CFLAGS := -Wall -Werror
+
 LOCAL_SHARED_LIBRARIES := \
     libbase \
     libcutils \
@@ -65,6 +67,8 @@
 LOCAL_SRC_FILES := \
     service.cpp
 
+LOCAL_CFLAGS := -Wall -Werror
+
 LOCAL_SHARED_LIBRARIES := \
     libhidlbase \
     libhidltransport \