Fix unused-parameter warnings

These are exposed when frameworks/av/include is moved from being a
system include directory to a normal include directory.

Test: m -j checkbuild
Change-Id: I0e3787fbee70339f7dcbc979f448800ecfff0f17
Merged-In: I0e3787fbee70339f7dcbc979f448800ecfff0f17
diff --git a/include/media/AudioEffect.h b/include/media/AudioEffect.h
index 6af1962..7f6ccac 100644
--- a/include/media/AudioEffect.h
+++ b/include/media/AudioEffect.h
@@ -462,7 +462,7 @@
         }
 
         // IBinder::DeathRecipient
-        virtual void binderDied(const wp<IBinder>& who) {
+        virtual void binderDied(const wp<IBinder>& /*who*/) {
             sp<AudioEffect> effect = mEffect.promote();
             if (effect != 0) {
                 effect->binderDied();