features.c: Remove unneeded adsi.h include.

adsi.h is no longer used by features.c since parking was moved to a
module.

Change-Id: I2248b8a455225a17cb6ddaafd6c20c511a1eaf59

main/features.c

@@ -64,7 +64,6 @@ ASTERISK_REGISTER_FILE()
 #include "asterisk/cli.h"
 #include "asterisk/manager.h"
 #include "asterisk/utils.h"
-#include "asterisk/adsi.h"
 #include "asterisk/devicestate.h"
 #include "asterisk/audiohook.h"
 #include "asterisk/global_datastores.h"