Make private/bionic_page.h available as platform/bionic/page.h.

Bug: http://b/145825270
Test: treehugger
Change-Id: I52958f370c0df2c02cb8250e2cf0705d4e93e908
diff --git a/libc/private/CFIShadow.h b/libc/private/CFIShadow.h
index 1423d86..84fbea5 100644
--- a/libc/private/CFIShadow.h
+++ b/libc/private/CFIShadow.h
@@ -19,7 +19,7 @@
 
 #include <stdint.h>
 
-#include "private/bionic_page.h"
+#include "platform/bionic/page.h"
 #include "private/bionic_macros.h"
 
 constexpr unsigned kLibraryAlignmentBits = 18;