split gralloc_priv.h and make sure it is C friendly
diff --git a/modules/gralloc/allocator.h b/modules/gralloc/allocator.h
index 6823982..b0d89e9 100644
--- a/modules/gralloc/allocator.h
+++ b/modules/gralloc/allocator.h
@@ -21,7 +21,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
-#include "gralloc_priv.h"
+#include "gr.h"
 
 // ----------------------------------------------------------------------------