Add AMediaFormat functions to clear and copy

Also move NdkMediaFormat internals to libmedia to avoid a future circular
dependency between libmedia and libmediandk.

Bug: 111407253
Test: build, boot, play some files

Change-Id: I54d91439f216c3834726e5505afef40dc0d93e67
diff --git a/media/ndk/NdkMediaExtractor.cpp b/media/ndk/NdkMediaExtractor.cpp
index b5e60a4..8c1ac59 100644
--- a/media/ndk/NdkMediaExtractor.cpp
+++ b/media/ndk/NdkMediaExtractor.cpp
@@ -20,8 +20,8 @@
 
 #include <media/NdkMediaError.h>
 #include <media/NdkMediaExtractor.h>
+#include <media/NdkMediaFormatPriv.h>
 #include "NdkMediaDataSourcePriv.h"
-#include "NdkMediaFormatPriv.h"
 
 
 #include <inttypes.h>