Rename hb-*private.hh to hb-*.hh

Sorry for the noise, downstream custom builders.  Please adjust.

src/hb-ot-maxp-table.hh

diff --git a/src/hb-ot-maxp-table.hh b/src/hb-ot-maxp-table.hh
index 75aac4f..cd2a85e 100644
--- a/src/hb-ot-maxp-table.hh
+++ b/src/hb-ot-maxp-table.hh
@@ -27,7 +27,7 @@
 #ifndef HB_OT_MAXP_TABLE_HH
 #define HB_OT_MAXP_TABLE_HH
 
-#include "hb-open-type-private.hh"
+#include "hb-open-type.hh"
 #include "hb-subset-plan.hh"
 
 namespace OT {