Reorganize include .h files

As now the bufferhubd/*.h files are all under cc_library build rule, we
decide to move all these .h files into include/ folder as a part of the
library.

Also, the #include statements under bufferhubd/ are re-ordered as:
C lib
(blank line)
C++ lib
(blank line)
Android lib

Test: Build passed. No further tests because of no behavior changes.

Change-Id: I4b6f944c722447a1b08612b3be3f257808a2f261
diff --git a/services/vr/bufferhubd/buffer_node.cpp b/services/vr/bufferhubd/buffer_node.cpp
index de22bba..5a04d0c 100644
--- a/services/vr/bufferhubd/buffer_node.cpp
+++ b/services/vr/bufferhubd/buffer_node.cpp
@@ -1,6 +1,5 @@
-#include "buffer_node.h"
-
 #include <private/dvr/buffer_hub_defs.h>
+#include <private/dvr/buffer_node.h>
 
 namespace android {
 namespace dvr {