Move bionic_macros.h from private to platform.

Test: treehugger
Change-Id: Ie473914f4c8924c7240b3ac22093a9daf42fc948
diff --git a/libc/private/WriteProtected.h b/libc/private/WriteProtected.h
index 26c239c..8f5b32d 100644
--- a/libc/private/WriteProtected.h
+++ b/libc/private/WriteProtected.h
@@ -24,7 +24,7 @@
 
 #include <async_safe/log.h>
 
-#include "private/bionic_macros.h"
+#include "platform/bionic/macros.h"
 
 template <typename T>
 union WriteProtectedContents {