Fix build warning

warning: pointer of type 'void *' used in arithmetic
warning: enumeral and non-enumeral type in conditional expression

Change-Id: I7b8d626a636145ef648e3b5d0e77068216dd012e
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 2e2834c..ded7cf6 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -4122,7 +4122,7 @@
         TimedBuffer& head = mTimedBufferQueue.editItemAt(0);
 
         void* start = head.buffer()->pointer();
-        void* end   = head.buffer()->pointer() + head.buffer()->size();
+        void* end   = (char *) head.buffer()->pointer() + head.buffer()->size();
 
         if ((buffer->raw >= start) && (buffer->raw <= end)) {
             head.setPosition(head.position() +