modules/[call_control|mediaproxy]: proper assigment to NULL pointer

CC (clang) [M mediaproxy.so]          mediaproxy.o
mediaproxy.c:1929:27: warning: expression which evaluates to zero treated as a null pointer constant of type 'void *' [-Wnon-literal-null-conversion]
        *_params->param = MPInactive;
                          ^~~~~~~~~~

modules/call_control/call_control.c

@@ -985,7 +985,7 @@ __dialog_ended(struct dlg_cell *dlg, int type, struct dlg_cb_params *_params)
         if( !msg || msg == FAKED_REPLY)
             msg = _params->req;
         call_control_stop(msg, dlg->callid);
-        *_params->param = (void*)CCInactive;
+        *_params->param = NULL;
     }
 }
 

modules/mediaproxy/mediaproxy.c

@@ -1926,7 +1926,7 @@ __dialog_ended(struct dlg_cell *dlg, int type, struct dlg_cb_params *_params)
 {
     if ((int)(long)*_params->param == MPActive) {
         end_media_session(dlg->callid, dlg->tag[DLG_CALLER_LEG], dlg->tag[DLG_CALLEE_LEG]);
-        *_params->param = MPInactive;
+        *_params->param = NULL;
     }
 }