abcio.h: correct the ordering of arguments

fw/abcio.h

@@ -28,7 +28,7 @@ struct abc_dev {
 
     void (*callback_out)(struct abc_dev *, uint8_t data);
     void (*callback_inp)(struct abc_dev *);
-    void (*callback_cmd)(struct abc_dev *, uint8_t addr, uint8_t data);
+    void (*callback_cmd)(struct abc_dev *, uint8_t data, uint8_t addr);
     void (*callback_status)(struct abc_dev *);
 };