Add MPEG 2 codec

This patch introduces the support of MPEG2 video decoding. It basically
just copies data from VA's frame/slice headers data structures to v4l's
MPEG2 frame header extended controls data structures.

src/mpeg2.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2016 Florent Revest, <florent.revest@free-electrons.com>
+ *               2007 Intel Corporation. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _MPEG2_H_
+#define _MPEG2_H_
+
+#include <va/va_backend.h>
+
+#include "context.h"
+#include "buffer.h"
+
+#include "surface.h"
+
+VAStatus sunxi_cedrus_render_mpeg2_slice_data(VADriverContextP ctx,
+		object_context_p obj_context, object_surface_p obj_surface,
+		object_buffer_p obj_buffer);
+
+VAStatus sunxi_cedrus_render_mpeg2_picture_parameter(VADriverContextP ctx,
+		object_context_p obj_context, object_surface_p obj_surface,
+		object_buffer_p obj_buffer);
+
+#endif /* _MPEG2_H_ */