[mpp_compat]: Add mpp compatible spec module

This module is for backward / forward compatiblity with external users.
1. Support compatible feature query.
2. Support update user program compatible feature update.

Change-Id: I7661f17c442eca0a0d0d57d2a35efdb5fd88be72
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>

osal/inc/mpp_compat_impl.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 Rockchip Electronics Co. LTD
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __MPP_COMPAT_IMPL_H__
+#define __MPP_COMPAT_IMPL_H__
+
+#include "rk_type.h"
+
+extern RK_S32 *compat_ext_fbc_buf_size;
+extern RK_S32 *compat_ext_async_input;
+
+#endif /*__MPP_COMPAT_IMPL_H__*/