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/producer_channel.cpp b/services/vr/bufferhubd/producer_channel.cpp
index 19d48f2..057d4f4 100644
--- a/services/vr/bufferhubd/producer_channel.cpp
+++ b/services/vr/bufferhubd/producer_channel.cpp
@@ -1,19 +1,18 @@
-#include "producer_channel.h"
-
-#include <log/log.h>
-#include <sync/sync.h>
 #include <sys/epoll.h>
 #include <sys/eventfd.h>
 #include <sys/poll.h>
-#include <utils/Trace.h>
 
 #include <algorithm>
 #include <atomic>
 #include <thread>
 
+#include <log/log.h>
 #include <private/dvr/bufferhub_rpc.h>
-#include "buffer_channel.h"
-#include "consumer_channel.h"
+#include <private/dvr/buffer_channel.h>
+#include <private/dvr/consumer_channel.h>
+#include <private/dvr/producer_channel.h>
+#include <sync/sync.h>
+#include <utils/Trace.h>
 
 using android::pdx::BorrowedHandle;
 using android::pdx::ErrorStatus;