ndk: 64-bit compile warnings

Change-Id: I214973a97547bf714e56e4596359cb2bd9cdea9c
diff --git a/media/ndk/NdkMediaExtractor.cpp b/media/ndk/NdkMediaExtractor.cpp
index 492e002..970a43c 100644
--- a/media/ndk/NdkMediaExtractor.cpp
+++ b/media/ndk/NdkMediaExtractor.cpp
@@ -133,13 +133,13 @@
 
 EXPORT
 media_status_t AMediaExtractor_selectTrack(AMediaExtractor *mData, size_t idx) {
-    ALOGV("selectTrack(%z)", idx);
+    ALOGV("selectTrack(%zu)", idx);
     return translate_error(mData->mImpl->selectTrack(idx));
 }
 
 EXPORT
 media_status_t AMediaExtractor_unselectTrack(AMediaExtractor *mData, size_t idx) {
-    ALOGV("unselectTrack(%z)", idx);
+    ALOGV("unselectTrack(%zu)", idx);
     return translate_error(mData->mImpl->unselectTrack(idx));
 }