Move bionic_macros.h from private to platform.

Test: treehugger
Change-Id: Ie473914f4c8924c7240b3ac22093a9daf42fc948
diff --git a/libc/stdio/printf_common.h b/libc/stdio/printf_common.h
index ad4fe35..4dc5ca1 100644
--- a/libc/stdio/printf_common.h
+++ b/libc/stdio/printf_common.h
@@ -48,7 +48,7 @@
 #include <unistd.h>
 #include <wchar.h>
 
-#include <private/bionic_macros.h>
+#include <platform/bionic/macros.h>
 
 #include "fvwrite.h"
 #include "gdtoa.h"