audiohal: Fix legacy shim compilation

Change-Id: I6cb1a2ed777283c6d81e6b6907cbddc3f2a25c4e
Test: make
diff --git a/media/libaudiohal/EffectBufferHalLocal.cpp b/media/libaudiohal/EffectBufferHalLocal.cpp
index 7e6ee85..9fe2c7b 100644
--- a/media/libaudiohal/EffectBufferHalLocal.cpp
+++ b/media/libaudiohal/EffectBufferHalLocal.cpp
@@ -75,10 +75,10 @@
 void EffectBufferHalLocal::commit() {
 }
 
-void EffectBufferHalLocal::update(size_t size) {
+void EffectBufferHalLocal::update(size_t) {
 }
 
-void EffectBufferHalLocal::commit(size_t size) {
+void EffectBufferHalLocal::commit(size_t) {
 }
 
 } // namespace android