libavfilter/dnn: move dnn files from libavfilter to libavfilter/dnn

it is expected that there will be more files to support native mode,
so put all the dnn codes under libavfilter/dnn

The main change of this patch is to move the file location, see below:
modified:   libavfilter/Makefile
new file:   libavfilter/dnn/Makefile
renamed:    libavfilter/dnn_backend_native.c -> libavfilter/dnn/dnn_backend_native.c
renamed:    libavfilter/dnn_backend_native.h -> libavfilter/dnn/dnn_backend_native.h
renamed:    libavfilter/dnn_backend_tf.c -> libavfilter/dnn/dnn_backend_tf.c
renamed:    libavfilter/dnn_backend_tf.h -> libavfilter/dnn/dnn_backend_tf.h
renamed:    libavfilter/dnn_interface.c -> libavfilter/dnn/dnn_interface.c

Signed-off-by: Guo, Yejun <yejun.guo@intel.com>
Signed-off-by: Pedro Arthur <bygrandao@gmail.com>

libavfilter/Makefile

@@ -26,9 +26,8 @@ OBJS-$(HAVE_THREADS)                         += pthread.o
 
 # subsystems
 OBJS-$(CONFIG_QSVVPP)                        += qsvvpp.o
-DNN-OBJS-$(CONFIG_LIBTENSORFLOW)             += dnn_backend_tf.o
-OBJS-$(CONFIG_DNN)                           += dnn_interface.o dnn_backend_native.o $(DNN-OBJS-yes)
 OBJS-$(CONFIG_SCENE_SAD)                     += scene_sad.o
+include $(SRC_PATH)/libavfilter/dnn/Makefile
 
 # audio filters
 OBJS-$(CONFIG_ABENCH_FILTER)                 += f_bench.o

libavfilter/dnn/Makefile

@@ -0,0 +1,6 @@
+OBJS-$(CONFIG_DNN)                           += dnn/dnn_interface.o
+OBJS-$(CONFIG_DNN)                           += dnn/dnn_backend_native.o
+
+DNN-OBJS-$(CONFIG_LIBTENSORFLOW)             += dnn/dnn_backend_tf.o
+
+OBJS-$(CONFIG_DNN)                           += $(DNN-OBJS-yes)

libavfilter/dnn/dnn_backend_native.h

@@ -24,10 +24,10 @@
  */
 
 
-#ifndef AVFILTER_DNN_BACKEND_NATIVE_H
-#define AVFILTER_DNN_BACKEND_NATIVE_H
+#ifndef AVFILTER_DNN_DNN_BACKEND_NATIVE_H
+#define AVFILTER_DNN_DNN_BACKEND_NATIVE_H
 
-#include "dnn_interface.h"
+#include "../dnn_interface.h"
 #include "libavformat/avio.h"
 
 typedef enum {INPUT, CONV, DEPTH_TO_SPACE} DNNLayerType;

libavfilter/dnn/dnn_backend_tf.h

@@ -24,10 +24,10 @@
  */
 
 
-#ifndef AVFILTER_DNN_BACKEND_TF_H
-#define AVFILTER_DNN_BACKEND_TF_H
+#ifndef AVFILTER_DNN_DNN_BACKEND_TF_H
+#define AVFILTER_DNN_DNN_BACKEND_TF_H
 
-#include "dnn_interface.h"
+#include "../dnn_interface.h"
 
 DNNModel *ff_dnn_load_model_tf(const char *model_filename);
 

libavfilter/dnn/dnn_interface.c

@@ -23,7 +23,7 @@
  * Implements DNN module initialization with specified backend.
  */
 
-#include "dnn_interface.h"
+#include "../dnn_interface.h"
 #include "dnn_backend_native.h"
 #include "dnn_backend_tf.h"
 #include "libavutil/mem.h"