[BUG] AudioService: PlaybackActivityMonitor: fix exploding list

This CL fixes the growing list of Playback Monitor client by
comparing the cb.asBinder() object to correctly find
the previous registration.

Test: todo

Signed-off-by: Francois Gaffie <francois.gaffie@renault.com>
Change-Id: Ib4ad166f584fe60c2a1e5721f3ab51e9a4151d41

services/core/java/com/android/server/audio/PlaybackActivityMonitor.java

@@ -779,7 +779,7 @@ public final class PlaybackActivityMonitor
             // the same time if we still have a public client.
             while (clientIterator.hasNext()) {
                 PlayMonitorClient pmc = clientIterator.next();
-                if (pcdb.equals(pmc.mDispatcherCb)) {
+                if (pcdb.asBinder().equals(pmc.mDispatcherCb.asBinder())) {
                     pmc.release();
                     clientIterator.remove();
                 } else {