Use size_t for frame counts

Also fix typo: bufferCount should be frameCount.

Change-Id: Ibed539504db75ef99dc21c8ff1bf2987122063a5
diff --git a/media/libmedia/SoundPool.cpp b/media/libmedia/SoundPool.cpp
index b321e92..204e0ce 100644
--- a/media/libmedia/SoundPool.cpp
+++ b/media/libmedia/SoundPool.cpp
@@ -568,7 +568,7 @@
         }
 
         // initialize track
-        int afFrameCount;
+        size_t afFrameCount;
         uint32_t afSampleRate;
         audio_stream_type_t streamType = mSoundPool->streamType();
         if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {