[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>

test/mpp_info_test.c

@@ -19,6 +19,7 @@
 #include "mpp_log.h"
 #include "mpp_env.h"
 #include "mpp_info.h"
+#include "mpp_compat.h"
 
 int main()
 {
@@ -33,6 +34,8 @@ int main()
     show_mpp_version();
     mpp_env_set_u32("mpp_show_history", 0);
 
+    mpp_compat_show();
+
     return 0;
 }